diff --git a/src/features/accounts/components/accounts-view.tsx b/src/features/accounts/components/accounts-view.tsx
index eec7c68..c8a994a 100644
--- a/src/features/accounts/components/accounts-view.tsx
+++ b/src/features/accounts/components/accounts-view.tsx
@@ -11,6 +11,7 @@ import {
   Pencil,
   Plus,
 } from "lucide-react";
+import Link from "next/link";
 import { useState, useTransition } from "react";
 import { toast } from "sonner";
 import { IconBadge } from "@/components/appearance/swatch";
@@ -109,7 +110,12 @@ export function AccountsView({
       <li className={cn("flex items-center gap-3 p-3", a.archived && "opacity-60")}>
         <IconBadge icon={a.icon} color={a.color} />
         <div className="min-w-0 flex-1">
-          <p className="truncate font-medium">{a.name}</p>
+          <Link
+            href={`/islemler?hesap=${a.id}`}
+            className="block truncate font-medium hover:underline"
+          >
+            {a.name}
+          </Link>
           <div className="flex flex-wrap items-center gap-x-2 gap-y-1 text-xs text-muted-foreground">
             {a.type === "meal_card" && a.mealCardProvider ? (
               <span>{t.providers[a.mealCardProvider]}</span>
diff --git a/src/features/accounts/service.int.test.ts b/src/features/accounts/service.int.test.ts
index 1db1033..84ecd95 100644
--- a/src/features/accounts/service.int.test.ts
+++ b/src/features/accounts/service.int.test.ts
@@ -89,7 +89,9 @@ describe("“yalnızca ben” hesabı", () => {
       (await listAccounts(ids.user(user), cakir))!.accounts.find(
         (a) => a.name === "Ayşe — Pluxee",
       )!;
-    expect((await find("ayse")).balanceMinor).toBe(3_120_00);
+    // Hesap sahibi açılış ve güncel bakiyeyi görür (güncel = açılış + işlemler).
+    expect((await find("ayse")).openingBalanceMinor).toBe(3_120_00);
+    expect((await find("ayse")).balanceMinor).not.toBeNull();
     expect((await find("admin")).balanceMinor).toBeNull();
     expect((await find("emre")).balanceMinor).toBeNull();
     expect((await find("emre")).openingBalanceMinor).toBeNull();
@@ -104,7 +106,10 @@ describe("“yalnızca ben” hesabı", () => {
     );
     const without = (await listAccounts(ids.user("emre"), cakir))!.totals;
     expect(without.excludesHidden).toBe(true);
-    expect(withHidden.assetsMinor - without.assetsMinor).toBe(3_120_00);
+    const pluxee = (await listAccounts(ids.user("ayse"), cakir))!.accounts.find(
+      (a) => a.name === "Ayşe — Pluxee",
+    )!;
+    expect(withHidden.assetsMinor - without.assetsMinor).toBe(pluxee.balanceMinor);
     // Hesap sahibi kendi hesabını her zaman toplamda görür.
     const ayse = (await listAccounts(ids.user("ayse"), cakir))!.totals;
     expect(ayse.assetsMinor).toBe(withHidden.assetsMinor);
diff --git a/src/features/accounts/service.ts b/src/features/accounts/service.ts
index 4833842..08c9de5 100644
--- a/src/features/accounts/service.ts
+++ b/src/features/accounts/service.ts
@@ -1,6 +1,7 @@
 import "server-only";
 import { Types } from "mongoose";
 import { getHouseholdDetail, resolveMembership } from "@/features/households/service";
+import { computeAccountDeltas } from "@/features/transactions/service";
 import { tr } from "@/i18n/tr";
 import { fail, ok, type ActionResult } from "@/lib/action-result";
 import { diffFields, writeAudit } from "@/lib/audit";
@@ -94,12 +95,12 @@ type Lean = {
 const canSeeBalance = (a: Lean, viewerId: string) =>
   !a.isPrivate || String(a.ownerUserId) === viewerId;
 
-/** FAZ 6b: açılış bakiyesi + işlemler. Şimdilik açılış bakiyesi. */
-function computeBalance(a: Lean): number {
-  return a.openingBalanceMinor;
+/** Güncel bakiye = açılış bakiyesi + gerçekleşmiş işlemlerin etkisi (tek doğruluk kaynağı: işlemler). */
+function computeBalance(a: Lean, deltas: ReadonlyMap<string, number>): number {
+  return a.openingBalanceMinor + (deltas.get(String(a._id)) ?? 0);
 }
 
-function toView(a: Lean, viewerId: string): AccountView {
+function toView(a: Lean, viewerId: string, deltas: ReadonlyMap<string, number>): AccountView {
   const visible = canSeeBalance(a, viewerId);
   return {
     id: String(a._id),
@@ -113,7 +114,7 @@ function toView(a: Lean, viewerId: string): AccountView {
     archived: Boolean(a.archivedAt),
     isPrivate: a.isPrivate,
     ownerUserId: a.ownerUserId ? String(a.ownerUserId) : null,
-    balanceMinor: visible ? computeBalance(a) : null,
+    balanceMinor: visible ? computeBalance(a, deltas) : null,
     openingBalanceMinor: visible ? a.openingBalanceMinor : null,
     openingDate: toIstanbulYmd(a.openingDate),
     overdraft: a.overdraft?.enabled ? a.overdraft : null,
@@ -140,7 +141,10 @@ export async function listAccounts(
   const rows = (await AccountModel.find(filter).lean<Lean[]>()).sort(
     (a, b) => a.order - b.order || compareTr(a.name, b.name),
   );
-  const household = await HouseholdModel.findById(m.householdId).select({ settings: 1 }).lean();
+  const [household, deltas] = await Promise.all([
+    HouseholdModel.findById(m.householdId).select({ settings: 1 }).lean(),
+    computeAccountDeltas(m.householdId),
+  ]);
   const includePrivate = household?.settings?.includePrivateAccountsInTotals ?? true;
 
   const totals: AccountTotals = {
@@ -158,12 +162,12 @@ export async function listAccounts(
       continue;
     }
     if (!visible) totals.includesHidden = true;
-    const balance = computeBalance(a);
+    const balance = computeBalance(a, deltas);
     if (isLiabilityType(a.type)) totals.cardDebtMinor += balance;
     else totals.assetsMinor += balance;
   }
   totals.netMinor = totals.assetsMinor + totals.cardDebtMinor;
-  return { accounts: rows.map((a) => toView(a, userId)), totals };
+  return { accounts: rows.map((a) => toView(a, userId, deltas)), totals };
 }
 
 /** Form → belge alanları. Kart için açılış borcu negatif saklanır. */
diff --git a/src/features/transactions/actions.ts b/src/features/transactions/actions.ts
new file mode 100644
index 0000000..ffa62d8
--- /dev/null
+++ b/src/features/transactions/actions.ts
@@ -0,0 +1,105 @@
+"use server";
+
+import { revalidatePath } from "next/cache";
+import { z } from "zod";
+import { tr } from "@/i18n/tr";
+import { fail, ok, type ActionResult } from "@/lib/action-result";
+import { getHouseholdActionContext } from "@/lib/dal";
+import { transactionFormSchema } from "@/shared/schemas/transaction";
+import {
+  createTransaction,
+  getTransaction,
+  getTransactionFormOptions,
+  searchPayees,
+  setTransactionDeleted,
+  updateTransaction,
+  type PayeeSuggestion,
+  type TransactionDetail,
+  type TransactionFormOptions,
+} from "./service";
+
+const idSchema = z.string().regex(/^[a-f0-9]{24}$/i);
+
+/** zod hatalarını alan bazlı mesajlara çevirir ("splits.1.amount" gibi yollar korunur). */
+function fieldErrors(error: z.ZodError) {
+  const out: Record<string, string> = {};
+  for (const issue of error.issues) {
+    const key = issue.path.join(".");
+    if (key && !out[key]) out[key] = issue.message;
+  }
+  return out;
+}
+
+function revalidate() {
+  // Bakiye, liste ve (ileride) dashboard aynı veriden beslenir.
+  revalidatePath("/", "layout");
+}
+
+export async function createTransactionAction(
+  input: unknown,
+): Promise<ActionResult<{ id: string }>> {
+  const ctx = await getHouseholdActionContext("member");
+  if (!ctx) return fail(tr.common.unauthorized);
+  const parsed = transactionFormSchema.safeParse(input);
+  if (!parsed.success) return fail(tr.adminUsers.errors.checkFields, fieldErrors(parsed.error));
+  const result = await createTransaction(ctx.user.id, ctx.household.id, parsed.data);
+  if (result.ok) revalidate();
+  return result;
+}
+
+export async function updateTransactionAction(
+  transactionId: unknown,
+  input: unknown,
+): Promise<ActionResult> {
+  const ctx = await getHouseholdActionContext("member");
+  if (!ctx) return fail(tr.common.unauthorized);
+  const id = idSchema.safeParse(transactionId);
+  if (!id.success) return fail(tr.common.notFound);
+  const parsed = transactionFormSchema.safeParse(input);
+  if (!parsed.success) return fail(tr.adminUsers.errors.checkFields, fieldErrors(parsed.error));
+  const result = await updateTransaction(ctx.user.id, ctx.household.id, id.data, parsed.data);
+  if (result.ok) revalidate();
+  return result;
+}
+
+export async function setTransactionDeletedAction(
+  transactionId: unknown,
+  deleted: unknown,
+): Promise<ActionResult> {
+  const ctx = await getHouseholdActionContext("member");
+  if (!ctx) return fail(tr.common.unauthorized);
+  const id = idSchema.safeParse(transactionId);
+  const d = z.boolean().safeParse(deleted);
+  if (!id.success || !d.success) return fail(tr.common.genericError);
+  const result = await setTransactionDeleted(ctx.user.id, ctx.household.id, id.data, d.data);
+  if (result.ok) revalidate();
+  return result;
+}
+
+/** Form açılırken: yazılabilir hesaplar ve kategoriler (hızlı ekle her ekrandan çağırır). */
+export async function getTransactionFormOptionsAction(): Promise<
+  ActionResult<TransactionFormOptions>
+> {
+  const ctx = await getHouseholdActionContext("member");
+  if (!ctx) return fail(tr.common.unauthorized);
+  const options = await getTransactionFormOptions(ctx.user.id, ctx.household.id);
+  return options ? ok(options) : fail(tr.common.unauthorized);
+}
+
+export async function getTransactionAction(
+  transactionId: unknown,
+): Promise<ActionResult<TransactionDetail>> {
+  const ctx = await getHouseholdActionContext("viewer");
+  if (!ctx) return fail(tr.common.unauthorized);
+  const id = idSchema.safeParse(transactionId);
+  if (!id.success) return fail(tr.common.notFound);
+  const detail = await getTransaction(ctx.user.id, ctx.household.id, id.data);
+  return detail ? ok(detail) : fail(tr.common.notFound);
+}
+
+export async function searchPayeesAction(query: unknown): Promise<PayeeSuggestion[]> {
+  const ctx = await getHouseholdActionContext("member");
+  const q = z.string().max(80).safeParse(query);
+  if (!ctx || !q.success) return [];
+  return searchPayees(ctx.user.id, ctx.household.id, q.data);
+}
diff --git a/src/features/transactions/service.int.test.ts b/src/features/transactions/service.int.test.ts
new file mode 100644
index 0000000..dd84b05
--- /dev/null
+++ b/src/features/transactions/service.int.test.ts
@@ -0,0 +1,434 @@
+import { Types } from "mongoose";
+import { afterAll, beforeAll, describe, expect, it } from "vitest";
+import { createAccount, listAccounts } from "@/features/accounts/service";
+import { setCategoryArchived } from "@/features/categories/service";
+import { AccountModel } from "@/models/account";
+import { CategoryModel } from "@/models/category";
+import { TransactionModel } from "@/models/transaction";
+import { transactionFilterSchema, type TransactionForm } from "@/shared/schemas/transaction";
+import { transactionEffects } from "@/shared/transactions";
+import { setupSeededDb, teardownDb } from "@/test/seeded-db";
+import {
+  createTransaction,
+  exportTransactions,
+  getTransaction,
+  listTransactions,
+  searchPayees,
+  setTransactionDeleted,
+  updateTransaction,
+} from "./service";
+
+let ids: Awaited<ReturnType<typeof setupSeededDb>>;
+let cakir = "";
+let annemler = "";
+
+beforeAll(async () => {
+  ids = await setupSeededDb();
+  cakir = ids.household("Çakır Ailesi");
+  annemler = ids.household("Annemler");
+});
+afterAll(teardownDb);
+
+const acc = (name: string, householdId = cakir) =>
+  AccountModel.findOne({ householdId, name })
+    .lean()
+    .then((a) => String(a!._id));
+const cat = (key: string, householdId = cakir) =>
+  CategoryModel.findOne({ householdId, defaultKey: key })
+    .lean()
+    .then((c) => String(c!._id));
+const filters = (x: Record<string, string> = {}) => transactionFilterSchema.parse(x);
+
+function form(over: Partial<TransactionForm>): TransactionForm {
+  return {
+    type: "expense",
+    amount: 100_00,
+    date: "2026-06-15",
+    accountId: "",
+    toAccountId: null,
+    categoryId: null,
+    splits: [],
+    payee: "",
+    description: "",
+    tags: [],
+    ...over,
+  };
+}
+
+async function mustCreate(user: string, f: TransactionForm, householdId = cakir) {
+  const r = await createTransaction(ids.user(user), householdId, f);
+  if (!r.ok) throw new Error(`oluşturulamadı: ${r.error} ${JSON.stringify(r.fieldErrors)}`);
+  return r.data.id;
+}
+
+describe("bakiye tutarlılığı", () => {
+  let bank = "";
+  let card = "";
+
+  it("gelir, gider, kart harcaması, karta transfer ve bölünmüş işlem bakiyeye doğru yansır", async () => {
+    const base = {
+      institution: "",
+      mealCardProvider: null,
+      openingDate: "2026-01-01",
+      color: "blue" as const,
+      icon: "landmark" as const,
+      ownerUserId: null,
+      isPrivate: false,
+      overdraftEnabled: false,
+      overdraftLimit: 0,
+      overdraftMonthlyRate: null,
+      overdraftStatementDay: null,
+      cardLimit: 0,
+      cardStatementDay: 1,
+      cardDueKind: "daysAfter" as const,
+      cardDueValue: 10,
+      cardPaymentAccountId: null,
+    };
+    const b = await createAccount(ids.user("ayse"), cakir, {
+      ...base,
+      name: "T Banka",
+      type: "bank",
+      openingBalance: 1_000_00,
+    });
+    const c = await createAccount(ids.user("ayse"), cakir, {
+      ...base,
+      name: "T Kart",
+      type: "credit_card",
+      openingBalance: 0,
+    });
+    bank = b.ok ? b.data.id : "";
+    card = c.ok ? c.data.id : "";
+    const gida = await cat("market.gida");
+    const temizlik = await cat("market.temizlik");
+
+    await mustCreate(
+      "ayse",
+      form({ type: "income", amount: 500_00, accountId: bank, categoryId: await cat("ek-gelir") }),
+    );
+    await mustCreate("ayse", form({ amount: 200_00, accountId: bank, categoryId: gida }));
+    await mustCreate("ayse", form({ amount: 300_00, accountId: card, categoryId: gida }));
+    await mustCreate(
+      "ayse",
+      form({ type: "transfer", amount: 300_00, accountId: bank, toAccountId: card }),
+    );
+    await mustCreate(
+      "ayse",
+      form({
+        amount: 120_00,
+        accountId: bank,
+        splits: [
+          { categoryId: gida, amount: 80_00, note: "" },
+          { categoryId: temizlik, amount: 40_00, note: "Deterjan" },
+        ],
+      }),
+    );
+
+    const balances = (await listAccounts(ids.user("ayse"), cakir))!.accounts;
+    expect(balances.find((a) => a.id === bank)?.balanceMinor).toBe(
+      1_000_00 + 500_00 - 200_00 - 300_00 - 120_00,
+    );
+    expect(balances.find((a) => a.id === card)?.balanceMinor).toBe(-300_00 + 300_00);
+  });
+
+  it("silme bakiyeden düşer, geri alma geri getirir", async () => {
+    const id = await mustCreate(
+      "emre",
+      form({ amount: 50_00, accountId: bank, categoryId: await cat("market.gida") }),
+    );
+    const bal = async () =>
+      (await listAccounts(ids.user("ayse"), cakir))!.accounts.find((a) => a.id === bank)!
+        .balanceMinor;
+    const before = await bal();
+    expect((await setTransactionDeleted(ids.user("emre"), cakir, id, true)).ok).toBe(true);
+    expect(await bal()).toBe(before! + 50_00);
+    expect(await getTransaction(ids.user("emre"), cakir, id)).toBeNull();
+    expect((await setTransactionDeleted(ids.user("emre"), cakir, id, false)).ok).toBe(true);
+    expect(await bal()).toBe(before);
+  });
+
+  it("tüm hesaplarda bakiye = açılış + Σ transactionEffects (bağımsız doğrulama)", async () => {
+    const accounts = await AccountModel.find({ householdId: cakir }).lean();
+    const txs = await TransactionModel.find({ householdId: cakir }).lean();
+    const expected = new Map(accounts.map((a) => [String(a._id), a.openingBalanceMinor]));
+    for (const tx of txs) {
+      for (const e of transactionEffects({
+        type: tx.type,
+        status: tx.status,
+        amountMinor: tx.amountMinor,
+        accountId: String(tx.accountId),
+        toAccountId: tx.toAccountId ? String(tx.toAccountId) : null,
+        deleted: Boolean(tx.deletedAt),
+      })) {
+        expected.set(e.accountId, (expected.get(e.accountId) ?? 0) + e.deltaMinor);
+      }
+    }
+    // ayse "yalnızca ben" hesabının sahibi; tüm bakiyeleri görür.
+    for (const a of (await listAccounts(ids.user("ayse"), cakir, { includeArchived: true }))!
+      .accounts) {
+      expect(a.balanceMinor, a.name).toBe(expected.get(a.id));
+    }
+  });
+});
+
+describe("doğrulama ve izolasyon", () => {
+  it("gider için gelir kategorisi, başka hanenin hesabı/kategorisi reddedilir", async () => {
+    const ziraat = await acc("Ziraat Maaş");
+    const r1 = await createTransaction(
+      ids.user("ayse"),
+      cakir,
+      form({ accountId: ziraat, categoryId: await cat("maas") }),
+    );
+    expect(r1.ok).toBe(false);
+    const r2 = await createTransaction(
+      ids.user("ayse"),
+      cakir,
+      form({ accountId: await acc("Nakit", annemler), categoryId: await cat("market.gida") }),
+    );
+    expect(r2.ok).toBe(false);
+    const r3 = await createTransaction(
+      ids.user("ayse"),
+      cakir,
+      form({ accountId: ziraat, categoryId: await cat("market.gida", annemler) }),
+    );
+    expect(r3.ok).toBe(false);
+    const r4 = await createTransaction(
+      ids.user("ayse"),
+      cakir,
+      form({
+        accountId: ziraat,
+        splits: [
+          { categoryId: await cat("market.gida"), amount: 50_00, note: "" },
+          { categoryId: await cat("market.gida", annemler), amount: 50_00, note: "" },
+        ],
+      }),
+    );
+    expect(r4.ok).toBe(false);
+    const r5 = await createTransaction(
+      ids.user("ayse"),
+      cakir,
+      form({
+        type: "transfer",
+        accountId: ziraat,
+        toAccountId: await acc("Vakıfbank Emekli", annemler),
+      }),
+    );
+    expect(r5.ok).toBe(false);
+  });
+
+  it("izleyici işlem giremez; başka hane üyesi işlemleri göremez", async () => {
+    const r = await createTransaction(
+      ids.user("zeynep"),
+      cakir,
+      form({ accountId: await acc("Cüzdan"), categoryId: await cat("market.gida") }),
+    );
+    expect(r.ok).toBe(false);
+    expect(await listTransactions(ids.user("fatma"), cakir, filters())).toBeNull();
+    const cakirTx = await TransactionModel.findOne({ householdId: cakir }).lean();
+    // fatma kendi hane kimliğiyle Çakır'ın işlemini isterse bulunamaz.
+    expect(await getTransaction(ids.user("fatma"), annemler, String(cakirTx!._id))).toBeNull();
+    expect(
+      (await setTransactionDeleted(ids.user("fatma"), annemler, String(cakirTx!._id), true)).ok,
+    ).toBe(false);
+  });
+});
+
+describe("“yalnızca ben” hesabı işlemleri", () => {
+  it("başkasından tamamen gizlenir; o hesaba yalnızca sahibi işlem girer", async () => {
+    const pluxee = await acc("Ayşe — Pluxee");
+    const tx = await TransactionModel.findOne({ householdId: cakir, accountId: pluxee }).lean();
+    const ofEmre = await listTransactions(ids.user("emre"), cakir, filters({ hesap: pluxee }));
+    expect(ofEmre!.total).toBe(0);
+    expect(await getTransaction(ids.user("emre"), cakir, String(tx!._id))).toBeNull();
+    const ofAyse = await listTransactions(ids.user("ayse"), cakir, filters({ hesap: pluxee }));
+    expect(ofAyse!.total).toBeGreaterThan(0);
+    const exportEmre = await exportTransactions(ids.user("emre"), cakir, filters());
+    expect(exportEmre!.some((r) => r.account === "Ayşe — Pluxee")).toBe(false);
+
+    const kafe = await cat("eglence.kafe");
+    expect(
+      (
+        await createTransaction(
+          ids.user("emre"),
+          cakir,
+          form({ accountId: pluxee, categoryId: kafe }),
+        )
+      ).ok,
+    ).toBe(false);
+    expect(
+      (
+        await updateTransaction(
+          ids.user("emre"),
+          cakir,
+          String(tx!._id),
+          form({ accountId: pluxee, categoryId: kafe }),
+        )
+      ).ok,
+    ).toBe(false);
+    expect(
+      (
+        await createTransaction(
+          ids.user("ayse"),
+          cakir,
+          form({ accountId: pluxee, categoryId: kafe }),
+        )
+      ).ok,
+    ).toBe(true);
+  });
+});
+
+describe("arşivli kategori", () => {
+  it("yeni işlemde kullanılamaz, mevcut işlemde korunur", async () => {
+    const giyim = await cat("giyim");
+    const cuzdan = await acc("Cüzdan");
+    const id = await mustCreate("ayse", form({ accountId: cuzdan, categoryId: giyim }));
+    expect((await setCategoryArchived(ids.user("ayse"), cakir, giyim, true)).ok).toBe(true);
+    expect(
+      (
+        await createTransaction(
+          ids.user("ayse"),
+          cakir,
+          form({ accountId: cuzdan, categoryId: giyim }),
+        )
+      ).ok,
+    ).toBe(false);
+    expect(
+      (
+        await updateTransaction(
+          ids.user("ayse"),
+          cakir,
+          id,
+          form({ accountId: cuzdan, categoryId: giyim, description: "düzeltme" }),
+        )
+      ).ok,
+    ).toBe(true);
+    await setCategoryArchived(ids.user("ayse"), cakir, giyim, false);
+  });
+});
+
+describe("filtreler", () => {
+  it("üst kategori filtresi alt kategorileri ve bölünmüş kalemleri kapsar", async () => {
+    const market = await cat("market");
+    const page = await listTransactions(ids.user("ayse"), cakir, filters({ kategori: market }));
+    expect(page!.total).toBe(
+      await TransactionModel.countDocuments({
+        householdId: cakir,
+        deletedAt: null,
+        effectiveCategoryIds: {
+          $in: await CategoryModel.find({
+            householdId: cakir,
+            $or: [{ _id: market }, { ancestors: new Types.ObjectId(market) }],
+          }).distinct("_id"),
+        },
+      }),
+    );
+    expect(page!.items.some((i) => i.splitCount > 0)).toBe(true);
+  });
+
+  it("tarih aralığı İstanbul gününe göre (gün dahil)", async () => {
+    const id = await mustCreate(
+      "ayse",
+      form({
+        date: "2026-01-15",
+        accountId: await acc("Cüzdan"),
+        categoryId: await cat("market.gida"),
+        payee: "Tarih Testi",
+      }),
+    );
+    const same = await listTransactions(
+      ids.user("ayse"),
+      cakir,
+      filters({ from: "2026-01-15", to: "2026-01-15", q: "tarih testi" }),
+    );
+    expect(same!.items.map((i) => i.id)).toEqual([id]);
+    const after = await listTransactions(
+      ids.user("ayse"),
+      cakir,
+      filters({ from: "2026-01-16", q: "tarih testi" }),
+    );
+    expect(after!.total).toBe(0);
+  });
+
+  it("Türkçe arama, tutar aralığı, kişi, etiket ve hesap (transfer hedefi dahil)", async () => {
+    const q = await listTransactions(ids.user("ayse"), cakir, filters({ q: "MİGROS" }));
+    expect(q!.total).toBeGreaterThan(0);
+    expect(q!.items.every((i) => i.payeeName === "Migros")).toBe(true);
+
+    const range = await listTransactions(
+      ids.user("ayse"),
+      cakir,
+      filters({ min: "1.000", max: "2.000" }),
+    );
+    expect(range!.items.every((i) => i.amountMinor >= 1_000_00 && i.amountMinor <= 2_000_00)).toBe(
+      true,
+    );
+
+    const byEmre = await listTransactions(
+      ids.user("ayse"),
+      cakir,
+      filters({ kisi: ids.user("emre") }),
+    );
+    expect(byEmre!.items.every((i) => i.createdBy.id === ids.user("emre"))).toBe(true);
+
+    const tagged = await listTransactions(ids.user("ayse"), cakir, filters({ etiket: "İndirim" }));
+    expect(tagged!.items.every((i) => i.tags.includes("indirim"))).toBe(true);
+
+    const cuzdan = await acc("Cüzdan");
+    const byAccount = await listTransactions(
+      ids.user("ayse"),
+      cakir,
+      filters({ hesap: cuzdan, type: "transfer" }),
+    );
+    expect(byAccount!.total).toBeGreaterThan(0);
+    expect(
+      byAccount!.items.every((i) => i.toAccount?.id === cuzdan || i.account.id === cuzdan),
+    ).toBe(true);
+  });
+
+  it("geçersiz filtre değerleri yok sayılır (enjeksiyon yok)", async () => {
+    const f = transactionFilterSchema.parse({
+      hesap: "{$ne:null}",
+      kategori: "x",
+      min: "abc",
+      sayfa: "-3",
+      q: ".*",
+    });
+    expect(f.hesap).toBeUndefined();
+    expect(f.kategori).toBeUndefined();
+    expect(f.min).toBeUndefined();
+    expect(f.sayfa).toBe(1);
+    // ".*" düz metin olarak aranır (regex kaçışı).
+    expect((await listTransactions(ids.user("ayse"), cakir, f))!.total).toBe(0);
+  });
+});
+
+describe("satıcı kuralları", () => {
+  it("son kullanılan kategori ve hesap önerilir", async () => {
+    const cuzdan = await acc("Cüzdan");
+    const ilac = await cat("saglik.ilac");
+    await mustCreate("ayse", form({ accountId: cuzdan, categoryId: ilac, payee: "Şifa Eczanesi" }));
+    const [s] = await searchPayees(ids.user("ayse"), cakir, "sifa");
+    expect(s).toMatchObject({
+      name: "Şifa Eczanesi",
+      lastAccountId: cuzdan,
+      lastCategoryId: ilac,
+      lastType: "expense",
+    });
+    // Başka hane satıcıyı görmez.
+    expect(await searchPayees(ids.user("fatma"), annemler, "sifa")).toEqual([]);
+  });
+});
+
+describe("CSV", () => {
+  it("bölünmüş işlem kalem başına satır üretir, işaret türe göre", async () => {
+    const rows = (await exportTransactions(ids.user("ayse"), cakir, filters()))!;
+    const split = await TransactionModel.findOne({
+      householdId: cakir,
+      "splits.1": { $exists: true },
+      deletedAt: null,
+    }).lean();
+    const lines = rows.filter((r) => r.no === String(split!._id));
+    expect(lines).toHaveLength(split!.splits.length);
+    expect(lines.reduce((a, r) => a + r.amountMinor, 0)).toBe(-split!.amountMinor);
+    expect(rows.find((r) => r.type === "income")!.amountMinor).toBeGreaterThan(0);
+  });
+});
diff --git a/src/features/transactions/service.ts b/src/features/transactions/service.ts
new file mode 100644
index 0000000..4869cd7
--- /dev/null
+++ b/src/features/transactions/service.ts
@@ -0,0 +1,727 @@
+import "server-only";
+import { Types, type PipelineStage } from "mongoose";
+import { resolveMembership } from "@/features/households/service";
+import { buildTree, toOptions, type CategoryOption } from "@/features/categories/tree";
+import { tr } from "@/i18n/tr";
+import { fail, ok, type ActionResult } from "@/lib/action-result";
+import { writeAudit } from "@/lib/audit";
+import { getDb } from "@/lib/db/mongo";
+import { toObjectId } from "@/lib/object-id";
+import { AccountModel } from "@/models/account";
+import { CategoryModel } from "@/models/category";
+import { PayeeModel } from "@/models/payee";
+import { TransactionModel } from "@/models/transaction";
+import type { AccountType } from "@/shared/accounts";
+import type { IconKey, Swatch } from "@/shared/appearance";
+import { istanbulDayStart, toIstanbulYmd } from "@/shared/dates";
+import type { CategoryKind } from "@/shared/schemas/category";
+import type { TransactionFilters, TransactionForm } from "@/shared/schemas/transaction";
+import { compareTr, foldTr } from "@/shared/search";
+import { normalizeTags, type TransactionStatus, type TransactionType } from "@/shared/transactions";
+
+/**
+ * İşlem servisi (Bölüm 6.3). Okuma: viewer; yazma: member.
+ * Başkasının "yalnızca ben" hesabına dokunan işlemler o kullanıcıdan tamamen gizlenir
+ * (işlemler bakiyeyi ele verir) ve bu hesaplara yalnızca hesap sahibi işlem girebilir.
+ */
+
+const t = tr.transactions;
+export const PAGE_SIZE = 25;
+const DAY_MS = 24 * 60 * 60 * 1000;
+
+// --- Hane bağlamı: hesaplar, kategoriler, görünürlük ---
+
+type AccountInfo = {
+  id: Types.ObjectId;
+  name: string;
+  type: AccountType;
+  archived: boolean;
+  hidden: boolean;
+  icon: IconKey;
+  color: Swatch;
+};
+
+type CategoryInfo = {
+  id: Types.ObjectId;
+  kind: CategoryKind;
+  name: string;
+  path: string;
+  archived: boolean;
+  icon: IconKey;
+  color: Swatch;
+  ancestors: string[];
+};
+
+async function loadContext(userId: string, householdId: string, minRole: "viewer" | "member") {
+  const m = await resolveMembership(userId, householdId, minRole);
+  if (!m) return null;
+  const [accounts, categories] = await Promise.all([
+    AccountModel.find({ householdId: m.householdId })
+      .select({ name: 1, type: 1, archivedAt: 1, isPrivate: 1, ownerUserId: 1, icon: 1, color: 1 })
+      .lean(),
+    CategoryModel.find({ householdId: m.householdId })
+      .select({
+        name: 1,
+        kind: 1,
+        parentId: 1,
+        order: 1,
+        archivedAt: 1,
+        icon: 1,
+        color: 1,
+        ancestors: 1,
+      })
+      .lean(),
+  ]);
+  const accountMap = new Map<string, AccountInfo>(
+    accounts.map((a) => [
+      String(a._id),
+      {
+        id: a._id,
+        name: a.name,
+        type: a.type,
+        archived: Boolean(a.archivedAt),
+        hidden: Boolean(a.isPrivate) && String(a.ownerUserId) !== userId,
+        icon: a.icon as IconKey,
+        color: a.color as Swatch,
+      },
+    ]),
+  );
+  const flat = categories.map((c) => ({
+    id: String(c._id),
+    kind: c.kind,
+    name: c.name,
+    parentId: c.parentId ? String(c.parentId) : null,
+    order: c.order,
+    archived: Boolean(c.archivedAt),
+  }));
+  const paths = new Map(
+    toOptions(buildTree(flat), { includeArchived: true }).map((o) => [o.id, o.path]),
+  );
+  const categoryMap = new Map<string, CategoryInfo>(
+    categories.map((c) => [
+      String(c._id),
+      {
+        id: c._id,
+        kind: c.kind,
+        name: c.name,
+        path: paths.get(String(c._id)) ?? c.name,
+        archived: Boolean(c.archivedAt),
+        icon: c.icon as IconKey,
+        color: c.color as Swatch,
+        ancestors: c.ancestors.map(String),
+      },
+    ]),
+  );
+  const hiddenAccountIds = [...accountMap.values()].filter((a) => a.hidden).map((a) => a.id);
+  return { m, accountMap, categoryMap, hiddenAccountIds, flatCategories: flat };
+}
+
+type Ctx = NonNullable<Awaited<ReturnType<typeof loadContext>>>;
+
+/** Gizli hesaplara dokunan işlemleri dışlayan temel filtre. */
+function baseFilter(ctx: Ctx): Record<string, unknown> {
+  const f: Record<string, unknown> = { householdId: ctx.m.householdId, deletedAt: null };
+  if (ctx.hiddenAccountIds.length) {
+    f.accountId = { $nin: ctx.hiddenAccountIds };
+    f.toAccountId = { $nin: ctx.hiddenAccountIds };
+  }
+  return f;
+}
+
+// --- Bakiye ---
+
+/**
+ * Hesap bazında işlem etkileri toplamı (kuruş): yalnızca posted ve silinmemiş işlemler.
+ * transactionEffects ile aynı kural: gelir +, gider −, transfer kaynak − / hedef +.
+ */
+export async function computeAccountDeltas(
+  householdId: Types.ObjectId,
+): Promise<Map<string, number>> {
+  const pipeline: PipelineStage[] = [
+    { $match: { householdId, status: "posted", deletedAt: null } },
+    {
+      $project: {
+        effects: [
+          {
+            a: "$accountId",
+            d: {
+              $cond: [
+                { $eq: ["$type", "income"] },
+                "$amountMinor",
+                { $multiply: ["$amountMinor", -1] },
+              ],
+            },
+          },
+          {
+            a: { $cond: [{ $eq: ["$type", "transfer"] }, "$toAccountId", null] },
+            d: "$amountMinor",
+          },
+        ],
+      },
+    },
+    { $unwind: "$effects" },
+    { $match: { "effects.a": { $ne: null } } },
+    { $group: { _id: "$effects.a", delta: { $sum: "$effects.d" } } },
+  ];
+  const rows = await TransactionModel.aggregate<{ _id: Types.ObjectId; delta: number }>(pipeline);
+  return new Map(rows.map((r) => [String(r._id), r.delta]));
+}
+
+// --- Doğrulama ---
+
+function checkAccount(ctx: Ctx, id: string | null, keep?: string | null): Types.ObjectId | null {
+  if (!id) return null;
+  const a = ctx.accountMap.get(id);
+  // Düzenlemede işlemin zaten bağlı olduğu arşivli hesap korunabilir.
+  if (!a || a.hidden || (a.archived && id !== keep)) return null;
+  return a.id;
+}
+
+function checkCategory(
+  ctx: Ctx,
+  id: string,
+  kind: CategoryKind,
+  keep: Set<string>,
+): Types.ObjectId | null {
+  const c = ctx.categoryMap.get(id);
+  if (!c || c.kind !== kind || (c.archived && !keep.has(id))) return null;
+  return c.id;
+}
+
+type Existing = {
+  accountId: Types.ObjectId;
+  toAccountId?: Types.ObjectId | null;
+  categoryId?: Types.ObjectId | null;
+  splits?: { categoryId: Types.ObjectId }[];
+};
+
+function buildDoc(
+  ctx: Ctx,
+  input: TransactionForm,
+  existing?: Existing,
+): ActionResult<Record<string, unknown>> {
+  const date = istanbulDayStart(input.date);
+  if (!date) return fail(tr.validation.date, { date: tr.validation.date });
+
+  const accountId = checkAccount(
+    ctx,
+    input.accountId,
+    existing ? String(existing.accountId) : null,
+  );
+  if (!accountId)
+    return fail(t.validation.accountInvalid, { accountId: t.validation.accountInvalid });
+
+  let toAccountId: Types.ObjectId | null = null;
+  let categoryId: Types.ObjectId | null = null;
+  let splits: { categoryId: Types.ObjectId; amountMinor: number; note: string }[] = [];
+
+  if (input.type === "transfer") {
+    toAccountId = checkAccount(
+      ctx,
+      input.toAccountId,
+      existing?.toAccountId ? String(existing.toAccountId) : null,
+    );
+    if (!toAccountId || toAccountId.equals(accountId)) {
+      return fail(t.validation.accountInvalid, { toAccountId: t.validation.accountInvalid });
+    }
+  } else {
+    const kind: CategoryKind = input.type;
+    const keep = new Set(
+      [existing?.categoryId, ...(existing?.splits ?? []).map((s) => s.categoryId)]
+        .filter(Boolean)
+        .map(String),
+    );
+    if (input.splits.length >= 2) {
+      for (const [i, s] of input.splits.entries()) {
+        const cid = checkCategory(ctx, s.categoryId, kind, keep);
+        if (!cid)
+          return fail(t.validation.categoryInvalid, {
+            [`splits.${i}.categoryId`]: t.validation.categoryInvalid,
+          });
+        splits.push({ categoryId: cid, amountMinor: s.amount, note: s.note });
+      }
+    } else {
+      categoryId = input.categoryId ? checkCategory(ctx, input.categoryId, kind, keep) : null;
+      if (!categoryId)
+        return fail(t.validation.categoryInvalid, { categoryId: t.validation.categoryInvalid });
+      splits = [];
+    }
+  }
+
+  const effective = [
+    ...new Set([categoryId, ...splits.map((s) => s.categoryId)].filter(Boolean).map(String)),
+  ].map((id) => new Types.ObjectId(id));
+  const payeeName = input.payee.trim();
+  return ok({
+    type: input.type,
+    date,
+    accountId,
+    toAccountId,
+    amountMinor: input.amount,
+    categoryId,
+    splits,
+    effectiveCategoryIds: effective,
+    payeeName,
+    description: input.description,
+    searchText: foldTr([payeeName, input.description, ...splits.map((s) => s.note)].join(" ")),
+    tags: normalizeTags(input.tags),
+  });
+}
+
+/** Satıcı kuralını günceller (son kategori ve hesap) ve kimliğini döner. */
+async function touchPayee(
+  householdId: Types.ObjectId,
+  name: string,
+  type: TransactionType,
+  accountId: Types.ObjectId,
+  categoryId: Types.ObjectId | null,
+): Promise<Types.ObjectId | null> {
+  if (!name) return null;
+  const doc = await PayeeModel.findOneAndUpdate(
+    { householdId, nameKey: foldTr(name) },
+    {
+      $setOnInsert: { householdId, nameKey: foldTr(name) },
+      $set: {
+        name,
+        lastType: type,
+        lastAccountId: accountId,
+        lastCategoryId: categoryId,
+        lastUsedAt: new Date(),
+      },
+      $inc: { useCount: 1 },
+    },
+    { upsert: true, returnDocument: "after" },
+  ).lean();
+  return doc?._id ?? null;
+}
+
+// --- Yazma ---
+
+export async function createTransaction(
+  actorId: string,
+  householdId: string,
+  input: TransactionForm,
+): Promise<ActionResult<{ id: string }>> {
+  const ctx = await loadContext(actorId, householdId, "member");
+  if (!ctx) return fail(tr.common.unauthorized);
+  const built = buildDoc(ctx, input);
+  if (!built.ok) return built;
+  const d = built.data as { accountId: Types.ObjectId; categoryId: Types.ObjectId | null };
+  // Bölünmüş işlemde tek bir kategori önerilemez; satıcı kuralı yalnızca hesabı hatırlar.
+  const payeeId = await touchPayee(
+    ctx.m.householdId,
+    input.payee,
+    input.type,
+    d.accountId,
+    d.categoryId,
+  );
+  const actor = new Types.ObjectId(actorId);
+  const doc = await TransactionModel.create({
+    ...built.data,
+    householdId: ctx.m.householdId,
+    status: "posted",
+    payeeId,
+    createdBy: actor,
+    updatedBy: actor,
+  });
+  return ok({ id: String(doc._id) });
+}
+
+async function loadOwnTransaction(
+  ctx: Ctx,
+  transactionId: string,
+  { includeDeleted = false } = {},
+) {
+  const id = toObjectId(transactionId);
+  if (!id) return null;
+  const filter: Record<string, unknown> = { ...baseFilter(ctx), _id: id };
+  if (includeDeleted) delete filter.deletedAt;
+  return TransactionModel.findOne(filter).lean();
+}
+
+export async function updateTransaction(
+  actorId: string,
+  householdId: string,
+  transactionId: string,
+  input: TransactionForm,
+): Promise<ActionResult> {
+  const ctx = await loadContext(actorId, householdId, "member");
+  if (!ctx) return fail(tr.common.unauthorized);
+  const current = await loadOwnTransaction(ctx, transactionId);
+  if (!current) return fail(tr.common.notFound);
+  const built = buildDoc(ctx, input, current);
+  if (!built.ok) return built;
+  const d = built.data as { accountId: Types.ObjectId; categoryId: Types.ObjectId | null };
+  const payeeId = await touchPayee(
+    ctx.m.householdId,
+    input.payee,
+    input.type,
+    d.accountId,
+    d.categoryId,
+  );
+  await TransactionModel.updateOne(
+    { _id: current._id, householdId: ctx.m.householdId },
+    { $set: { ...built.data, payeeId, updatedBy: new Types.ObjectId(actorId) } },
+  );
+  return ok(undefined);
+}
+
+export async function setTransactionDeleted(
+  actorId: string,
+  householdId: string,
+  transactionId: string,
+  deleted: boolean,
+): Promise<ActionResult> {
+  const ctx = await loadContext(actorId, householdId, "member");
+  if (!ctx) return fail(tr.common.unauthorized);
+  const current = await loadOwnTransaction(ctx, transactionId, { includeDeleted: true });
+  if (!current || Boolean(current.deletedAt) === deleted) return fail(tr.common.notFound);
+  const actor = new Types.ObjectId(actorId);
+  await TransactionModel.updateOne(
+    { _id: current._id, householdId: ctx.m.householdId },
+    { $set: { deletedAt: deleted ? new Date() : null, updatedBy: actor } },
+  );
+  await writeAudit({
+    action: deleted ? "transaction.delete" : "transaction.restore",
+    actorId: actor,
+    householdId: ctx.m.householdId,
+    targetType: "transaction",
+    targetId: transactionId,
+    diff: {
+      type: current.type,
+      amountMinor: current.amountMinor,
+      date: toIstanbulYmd(current.date),
+    },
+  });
+  return ok(undefined);
+}
+
+// --- Okuma ---
+
+export type TransactionListItem = {
+  id: string;
+  type: TransactionType;
+  status: TransactionStatus;
+  date: string;
+  amountMinor: number;
+  account: { id: string; name: string };
+  toAccount: { id: string; name: string } | null;
+  category: { id: string; name: string; path: string; icon: IconKey; color: Swatch } | null;
+  splitCount: number;
+  payeeName: string;
+  description: string;
+  tags: string[];
+  createdBy: { id: string; name: string };
+  attachmentCount: number;
+};
+
+export type TransactionDetail = TransactionListItem & {
+  splits: {
+    categoryId: string;
+    path: string;
+    icon: IconKey;
+    color: Swatch;
+    amountMinor: number;
+    note: string;
+  }[];
+  updatedBy: { id: string; name: string };
+  createdAt: string;
+  updatedAt: string;
+  /** Düzenleme formu için ham kimlikler. */
+  categoryId: string | null;
+};
+
+async function userNames(ids: Types.ObjectId[]): Promise<Map<string, string>> {
+  const unique = [...new Set(ids.map(String))].map((id) => new Types.ObjectId(id));
+  const users = await getDb()
+    .collection("user")
+    .find({ _id: { $in: unique } }, { projection: { name: 1 } })
+    .toArray();
+  return new Map(users.map((u) => [String(u._id), String(u.name ?? "—")]));
+}
+
+type LeanTx = Awaited<ReturnType<typeof TransactionModel.find>>[number] & {
+  _id: Types.ObjectId;
+  createdAt: Date;
+  updatedAt: Date;
+};
+
+function toItem(ctx: Ctx, tx: LeanTx, names: Map<string, string>): TransactionListItem {
+  const acc = (id: Types.ObjectId | null | undefined) => {
+    if (!id) return null;
+    const a = ctx.accountMap.get(String(id));
+    return { id: String(id), name: a?.name ?? "—" };
+  };
+  const cat = tx.categoryId ? ctx.categoryMap.get(String(tx.categoryId)) : undefined;
+  return {
+    id: String(tx._id),
+    type: tx.type,
+    status: tx.status,
+    date: toIstanbulYmd(tx.date),
+    amountMinor: tx.amountMinor,
+    account: acc(tx.accountId)!,
+    toAccount: acc(tx.toAccountId),
+    category: cat
+      ? { id: String(cat.id), name: cat.name, path: cat.path, icon: cat.icon, color: cat.color }
+      : null,
+    splitCount: tx.splits?.length ?? 0,
+    payeeName: tx.payeeName ?? "",
+    description: tx.description ?? "",
+    tags: tx.tags ?? [],
+    createdBy: { id: String(tx.createdBy), name: names.get(String(tx.createdBy)) ?? "—" },
+    attachmentCount: tx.attachmentCount ?? 0,
+  };
+}
+
+const escapeRegex = (s: string) => s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+
+function filterQuery(ctx: Ctx, f: TransactionFilters): Record<string, unknown> {
+  const q: Record<string, unknown> = baseFilter(ctx);
+  const and: Record<string, unknown>[] = [];
+  const from = f.from ? istanbulDayStart(f.from) : null;
+  const to = f.to ? istanbulDayStart(f.to) : null;
+  if (from || to) {
+    q.date = {
+      ...(from ? { $gte: from } : {}),
+      ...(to ? { $lt: new Date(to.getTime() + DAY_MS) } : {}),
+    };
+  }
+  if (f.type) q.type = f.type;
+  if (f.durum) q.status = f.durum;
+  if (f.hesap) {
+    const id = toObjectId(f.hesap);
+    // Gizli hesap filtresi sonuç vermez (baseFilter zaten dışlar).
+    and.push({ $or: [{ accountId: id }, { toAccountId: id }] });
+  }
+  if (f.kategori) {
+    // Alt kategoriler dahil.
+    const ids = [...ctx.categoryMap.values()]
+      .filter((c) => String(c.id) === f.kategori || c.ancestors.includes(f.kategori!))
+      .map((c) => c.id);
+    q.effectiveCategoryIds = { $in: ids };
+  }
+  if (f.kisi) q.createdBy = toObjectId(f.kisi);
+  if (f.min !== undefined || f.max !== undefined) {
+    q.amountMinor = {
+      ...(f.min !== undefined ? { $gte: f.min } : {}),
+      ...(f.max !== undefined ? { $lte: f.max } : {}),
+    };
+  }
+  if (f.etiket) q.tags = normalizeTags(f.etiket)[0] ?? "";
+  if (f.q) q.searchText = { $regex: escapeRegex(foldTr(f.q)) };
+  if (and.length) q.$and = and;
+  return q;
+}
+
+export type TransactionPage = {
+  items: TransactionListItem[];
+  total: number;
+  page: number;
+  pageCount: number;
+  sums: { incomeMinor: number; expenseMinor: number };
+};
+
+export async function listTransactions(
+  userId: string,
+  householdId: string,
+  filters: TransactionFilters,
+): Promise<TransactionPage | null> {
+  const ctx = await loadContext(userId, householdId, "viewer");
+  if (!ctx) return null;
+  const query = filterQuery(ctx, filters);
+  const [total, sumRows] = await Promise.all([
+    TransactionModel.countDocuments(query),
+    TransactionModel.aggregate<{ _id: TransactionType; sum: number }>([
+      {
+        $match: {
+          ...query,
+          status: query.status ?? "posted",
+          type: query.type ?? { $in: ["income", "expense"] },
+        },
+      },
+      { $group: { _id: "$type", sum: { $sum: "$amountMinor" } } },
+    ]),
+  ]);
+  const pageCount = Math.max(1, Math.ceil(total / PAGE_SIZE));
+  const page = Math.min(filters.sayfa, pageCount);
+  const rows = (await TransactionModel.find(query)
+    .sort({ date: -1, createdAt: -1 })
+    .skip((page - 1) * PAGE_SIZE)
+    .limit(PAGE_SIZE)
+    .lean()) as unknown as LeanTx[];
+  const names = await userNames(rows.map((r) => r.createdBy as Types.ObjectId));
+  return {
+    items: rows.map((r) => toItem(ctx, r, names)),
+    total,
+    page,
+    pageCount,
+    sums: {
+      incomeMinor: sumRows.find((r) => r._id === "income")?.sum ?? 0,
+      expenseMinor: sumRows.find((r) => r._id === "expense")?.sum ?? 0,
+    },
+  };
+}
+
+export async function getTransaction(
+  userId: string,
+  householdId: string,
+  transactionId: string,
+): Promise<TransactionDetail | null> {
+  const ctx = await loadContext(userId, householdId, "viewer");
+  if (!ctx) return null;
+  const tx = (await loadOwnTransaction(ctx, transactionId)) as unknown as LeanTx | null;
+  if (!tx) return null;
+  const names = await userNames([tx.createdBy as Types.ObjectId, tx.updatedBy as Types.ObjectId]);
+  return {
+    ...toItem(ctx, tx, names),
+    categoryId: tx.categoryId ? String(tx.categoryId) : null,
+    splits: (tx.splits ?? []).map((s) => {
+      const c = ctx.categoryMap.get(String(s.categoryId));
+      return {
+        categoryId: String(s.categoryId),
+        path: c?.path ?? "—",
+        icon: c?.icon ?? "tag",
+        color: c?.color ?? "slate",
+        amountMinor: s.amountMinor,
+        note: s.note ?? "",
+      };
+    }),
+    updatedBy: { id: String(tx.updatedBy), name: names.get(String(tx.updatedBy)) ?? "—" },
+    createdAt: new Date(tx.createdAt).toISOString(),
+    updatedAt: new Date(tx.updatedAt).toISOString(),
+  };
+}
+
+/** CSV için tüm eşleşen işlemler (sayfalama yok; üst sınır 20.000). Bölünmüş işlem kalem başına satır. */
+export async function exportTransactions(
+  userId: string,
+  householdId: string,
+  filters: TransactionFilters,
+) {
+  const ctx = await loadContext(userId, householdId, "viewer");
+  if (!ctx) return null;
+  const rows = await TransactionModel.find(filterQuery(ctx, filters))
+    .sort({ date: -1, createdAt: -1 })
+    .limit(20_000)
+    .lean();
+  const names = await userNames(rows.map((r) => r.createdBy as Types.ObjectId));
+  const accountName = (id: Types.ObjectId | null | undefined) =>
+    id ? (ctx.accountMap.get(String(id))?.name ?? "") : "";
+  const categoryPath = (id: Types.ObjectId | null | undefined) =>
+    id ? (ctx.categoryMap.get(String(id))?.path ?? "") : "";
+  const sign = (type: TransactionType) => (type === "income" ? 1 : type === "expense" ? -1 : 1);
+  const out: {
+    no: string;
+    date: string;
+    type: TransactionType;
+    status: TransactionStatus;
+    account: string;
+    toAccount: string;
+    category: string;
+    payee: string;
+    description: string;
+    note: string;
+    tags: string;
+    amountMinor: number;
+    createdBy: string;
+  }[] = [];
+  for (const r of rows) {
+    const common = {
+      no: String(r._id),
+      date: toIstanbulYmd(r.date),
+      type: r.type,
+      status: r.status,
+      account: accountName(r.accountId),
+      toAccount: accountName(r.toAccountId),
+      payee: r.payeeName ?? "",
+      description: r.description ?? "",
+      tags: (r.tags ?? []).join(", "),
+      createdBy: names.get(String(r.createdBy)) ?? "",
+    };
+    if (r.splits?.length) {
+      for (const s of r.splits) {
+        out.push({
+          ...common,
+          category: categoryPath(s.categoryId),
+          note: s.note ?? "",
+          amountMinor: sign(r.type) * s.amountMinor,
+        });
+      }
+    } else {
+      out.push({
+        ...common,
+        category: categoryPath(r.categoryId),
+        note: "",
+        amountMinor: sign(r.type) * r.amountMinor,
+      });
+    }
+  }
+  return out;
+}
+
+// --- Form seçenekleri ve satıcı önerileri ---
+
+export type TransactionFormOptions = {
+  accounts: { id: string; name: string; type: AccountType; icon: IconKey; color: Swatch }[];
+  categories: CategoryOption[];
+  categoryAppearance: Record<string, { icon: IconKey; color: Swatch }>;
+};
+
+export async function getTransactionFormOptions(
+  userId: string,
+  householdId: string,
+): Promise<TransactionFormOptions | null> {
+  const ctx = await loadContext(userId, householdId, "viewer");
+  if (!ctx) return null;
+  const accounts = (
+    await AccountModel.find({ householdId: ctx.m.householdId, archivedAt: null })
+      .select({ name: 1, type: 1, icon: 1, color: 1, order: 1, isPrivate: 1, ownerUserId: 1 })
+      .lean()
+  )
+    .filter((a) => !a.isPrivate || String(a.ownerUserId) === userId)
+    .sort((a, b) => a.order - b.order || compareTr(a.name, b.name))
+    .map((a) => ({
+      id: String(a._id),
+      name: a.name,
+      type: a.type,
+      icon: a.icon as IconKey,
+      color: a.color as Swatch,
+    }));
+  const categories = toOptions(buildTree(ctx.flatCategories));
+  const categoryAppearance = Object.fromEntries(
+    [...ctx.categoryMap.values()].map((c) => [String(c.id), { icon: c.icon, color: c.color }]),
+  );
+  return { accounts, categories, categoryAppearance };
+}
+
+export type PayeeSuggestion = {
+  name: string;
+  lastType: TransactionType;
+  lastCategoryId: string | null;
+  lastAccountId: string | null;
+};
+
+/** Satıcı önerileri: ada göre (Türkçe normalize, baştan veya içinden), kullanım sıklığına göre. */
+export async function searchPayees(
+  userId: string,
+  householdId: string,
+  query: string,
+): Promise<PayeeSuggestion[]> {
+  const ctx = await loadContext(userId, householdId, "viewer");
+  if (!ctx) return [];
+  const key = foldTr(query);
+  const filter: Record<string, unknown> = { householdId: ctx.m.householdId };
+  if (key) filter.nameKey = { $regex: escapeRegex(key) };
+  const rows = await PayeeModel.find(filter).sort({ useCount: -1, lastUsedAt: -1 }).limit(8).lean();
+  return rows.map((p) => {
+    const acc = p.lastAccountId ? ctx.accountMap.get(String(p.lastAccountId)) : undefined;
+    const cat = p.lastCategoryId ? ctx.categoryMap.get(String(p.lastCategoryId)) : undefined;
+    return {
+      name: p.name,
+      lastType: p.lastType,
+      // Öneri yalnızca hâlâ kullanılabilir hesap/kategoriyi gösterir.
+      lastAccountId: acc && !acc.hidden && !acc.archived ? String(acc.id) : null,
+      lastCategoryId: cat && !cat.archived ? String(cat.id) : null,
+    };
+  });
+}
diff --git a/src/models/audit-log.ts b/src/models/audit-log.ts
index 37a9484..c52b775 100644
--- a/src/models/audit-log.ts
+++ b/src/models/audit-log.ts
@@ -24,6 +24,8 @@ export const AUDIT_ACTIONS = [
   "category.archive",
   "category.unarchive",
   "category.move",
+  "transaction.delete",
+  "transaction.restore",
 ] as const;
 export type AuditAction = (typeof AUDIT_ACTIONS)[number];
 
diff --git a/src/models/payee.ts b/src/models/payee.ts
new file mode 100644
index 0000000..1afbb39
--- /dev/null
+++ b/src/models/payee.ts
@@ -0,0 +1,25 @@
+import { model, models, Schema, type InferSchemaType, type Model } from "mongoose";
+import { TRANSACTION_TYPES } from "@/shared/transactions";
+
+/** Satıcı / karşı taraf ve "akıllı giriş" kuralı: son kullanılan kategori ve hesap (Bölüm 6.3). */
+const payeeSchema = new Schema(
+  {
+    householdId: { type: Schema.Types.ObjectId, required: true },
+    name: { type: String, required: true, trim: true, maxlength: 80 },
+    nameKey: { type: String, required: true },
+    lastType: { type: String, enum: TRANSACTION_TYPES, default: "expense" },
+    lastCategoryId: { type: Schema.Types.ObjectId, default: null },
+    lastAccountId: { type: Schema.Types.ObjectId, default: null },
+    useCount: { type: Number, default: 0 },
+    lastUsedAt: { type: Date, default: () => new Date() },
+  },
+  { timestamps: true, collection: "payees" },
+);
+
+payeeSchema.index({ householdId: 1, nameKey: 1 }, { unique: true });
+payeeSchema.index({ householdId: 1, useCount: -1 });
+
+export type Payee = InferSchemaType<typeof payeeSchema>;
+
+export const PayeeModel: Model<Payee> =
+  (models.Payee as Model<Payee> | undefined) ?? model<Payee>("Payee", payeeSchema);
diff --git a/src/models/transaction.ts b/src/models/transaction.ts
new file mode 100644
index 0000000..ac1e83c
--- /dev/null
+++ b/src/models/transaction.ts
@@ -0,0 +1,75 @@
+import { model, models, Schema, type InferSchemaType, type Model } from "mongoose";
+import { TRANSACTION_STATUSES, TRANSACTION_TYPES } from "@/shared/transactions";
+
+/**
+ * İşlem (Bölüm 6.3). `amountMinor` her zaman pozitif; işaret türden gelir (transactionEffects).
+ * Bakiyenin tek doğruluk kaynağıdır. Silme yumuşaktır (`deletedAt`).
+ */
+const splitSchema = new Schema(
+  {
+    categoryId: { type: Schema.Types.ObjectId, required: true },
+    amountMinor: { type: Number, required: true, min: 1 },
+    note: { type: String, default: "", maxlength: 120 },
+  },
+  { _id: true },
+);
+
+const transactionSchema = new Schema(
+  {
+    householdId: { type: Schema.Types.ObjectId, required: true },
+    type: { type: String, enum: TRANSACTION_TYPES, required: true },
+    status: { type: String, enum: TRANSACTION_STATUSES, default: "posted" },
+    /** İstanbul gününün başlangıç anı (UTC). */
+    date: { type: Date, required: true },
+    accountId: { type: Schema.Types.ObjectId, required: true },
+    toAccountId: { type: Schema.Types.ObjectId, default: null },
+    amountMinor: { type: Number, required: true, min: 1 },
+    /** Bölünmemiş gelir/giderde kategori; bölünmüşte null ve kalemler `splits`te. */
+    categoryId: { type: Schema.Types.ObjectId, default: null },
+    splits: { type: [splitSchema], default: [] },
+    /** Kategori filtresi/raporlar için: categoryId veya kalem kategorileri (tekilleştirilmiş). */
+    effectiveCategoryIds: { type: [Schema.Types.ObjectId], default: [] },
+    payeeId: { type: Schema.Types.ObjectId, default: null },
+    payeeName: { type: String, default: "", maxlength: 80 },
+    description: { type: String, default: "", maxlength: 500 },
+    /** Arama için normalize metin (açıklama + satıcı + kalem notları). */
+    searchText: { type: String, default: "" },
+    tags: { type: [String], default: [] },
+    attachmentCount: { type: Number, default: 0 },
+    // İleri fazlar: planlı işlem kuralı (7), taksit (7), kart dönemi (7), cari (8).
+    recurringRuleId: { type: Schema.Types.ObjectId, default: null },
+    installment: {
+      type: new Schema(
+        { planId: Schema.Types.ObjectId, index: Number, count: Number },
+        { _id: false },
+      ),
+      default: null,
+    },
+    statementId: { type: Schema.Types.ObjectId, default: null },
+    contactId: { type: Schema.Types.ObjectId, default: null },
+    reconciledAt: { type: Date, default: null },
+    deletedAt: { type: Date, default: null },
+    /** Seed verisinin idempotent yüklenmesi için sabit anahtar. */
+    seedRef: { type: String, default: null },
+    createdBy: { type: Schema.Types.ObjectId, required: true },
+    updatedBy: { type: Schema.Types.ObjectId, required: true },
+  },
+  { timestamps: true, collection: "transactions" },
+);
+
+transactionSchema.index({ householdId: 1, deletedAt: 1, date: -1, createdAt: -1 });
+transactionSchema.index({ householdId: 1, status: 1, date: 1 });
+transactionSchema.index({ householdId: 1, accountId: 1, date: -1 });
+transactionSchema.index({ householdId: 1, toAccountId: 1, date: -1 });
+transactionSchema.index({ householdId: 1, effectiveCategoryIds: 1, date: -1 });
+transactionSchema.index({ householdId: 1, tags: 1 });
+transactionSchema.index(
+  { householdId: 1, seedRef: 1 },
+  { unique: true, partialFilterExpression: { seedRef: { $type: "string" } } },
+);
+
+export type Transaction = InferSchemaType<typeof transactionSchema>;
+
+export const TransactionModel: Model<Transaction> =
+  (models.Transaction as Model<Transaction> | undefined) ??
+  model<Transaction>("Transaction", transactionSchema);