diff --git a/src/lib/usage-recorder.ts b/src/lib/usage-recorder.ts
new file mode 100644
index 00000000..2debabca
--- /dev/null
+++ b/src/lib/usage-recorder.ts
@@ -0,0 +1,139 @@
+import consola from "consola"
+
+import type { Account } from "./account-pool"
+import type { NormalizedUsage } from "./usage-normalizer"
+
+import { getDb } from "./db"
+
+export type UsageEndpoint = "chat.completions" | "messages" | "embeddings"
+export type UpstreamFormat = "openai" | "anthropic"
+export type UsageStatus = "ok" | "error" | "aborted"
+
+export interface RecordUsageInput {
+  account: Account
+  modelId: string
+  endpoint: UsageEndpoint
+  upstreamFormat: UpstreamFormat
+  isStreaming: boolean
+  usage: NormalizedUsage
+  durationMs: number
+  status: UsageStatus
+  requestId?: string
+  isInternal?: boolean
+}
+
+interface PricingRow {
+  input_per_mtok: number | null
+  cached_input_per_mtok: number | null
+  output_per_mtok: number | null
+  reasoning_per_mtok: number | null
+  premium_unit_price: number | null
+  premium_multiplier: number | null
+}
+
+/**
+ * Record a single upstream usage event and atomically update the daily
+ * aggregate. Errors are swallowed (logged via consola); recorder failure
+ * must not break the caller's response path.
+ */
+export function recordUsage(input: RecordUsageInput): void {
+  if (input.isInternal) return
+
+  try {
+    const db = getDb()
+    const ts = Date.now()
+
+    const pricing = db
+      .query<PricingRow, [string]>(
+        `SELECT input_per_mtok,
+                cached_input_per_mtok,
+                output_per_mtok,
+                reasoning_per_mtok,
+                premium_unit_price,
+                premium_multiplier
+           FROM model_pricing
+          WHERE model_id = ?`,
+      )
+      .get(input.modelId)
+
+    const inputPrice = pricing?.input_per_mtok ?? null
+    const cachedInputPrice = pricing?.cached_input_per_mtok ?? null
+    const outputPrice = pricing?.output_per_mtok ?? null
+    const reasoningPrice = pricing?.reasoning_per_mtok ?? null
+    const premiumUnitPrice = pricing?.premium_unit_price ?? null
+    const premiumMultiplier = pricing?.premium_multiplier ?? null
+    const premiumRequestCount = premiumMultiplier ?? 0
+
+    const insertEvent = db.prepare(
+      `INSERT INTO usage_events (
+         ts, account_name, model_id, endpoint, upstream_format, is_streaming,
+         input_tokens, cached_input_tokens, output_tokens, reasoning_tokens,
+         total_tokens, premium_request_count,
+         input_price_snapshot, cached_input_price_snapshot,
+         output_price_snapshot, reasoning_price_snapshot,
+         premium_unit_price_snapshot, premium_multiplier_snapshot,
+         request_id, status, duration_ms
+       ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+    )
+
+    const upsertDaily = db.prepare(
+      `INSERT INTO usage_daily (
+         day, account_name, model_id, endpoint,
+         req_count, input_tokens, cached_input_tokens,
+         output_tokens, reasoning_tokens, total_tokens, premium_requests
+       ) VALUES (
+         date(?/1000, 'unixepoch', 'localtime'),
+         ?, ?, ?, 1, ?, ?, ?, ?, ?, ?
+       )
+       ON CONFLICT(day, account_name, model_id, endpoint) DO UPDATE SET
+         req_count = req_count + 1,
+         input_tokens = input_tokens + excluded.input_tokens,
+         cached_input_tokens = cached_input_tokens + excluded.cached_input_tokens,
+         output_tokens = output_tokens + excluded.output_tokens,
+         reasoning_tokens = reasoning_tokens + excluded.reasoning_tokens,
+         total_tokens = total_tokens + excluded.total_tokens,
+         premium_requests = premium_requests + excluded.premium_requests`,
+    )
+
+    const tx = db.transaction(() => {
+      insertEvent.run(
+        ts,
+        input.account.name,
+        input.modelId,
+        input.endpoint,
+        input.upstreamFormat,
+        input.isStreaming ? 1 : 0,
+        input.usage.inputTokens,
+        input.usage.cachedInputTokens,
+        input.usage.outputTokens,
+        input.usage.reasoningTokens,
+        input.usage.totalTokens,
+        premiumRequestCount,
+        inputPrice,
+        cachedInputPrice,
+        outputPrice,
+        reasoningPrice,
+        premiumUnitPrice,
+        premiumMultiplier,
+        input.requestId ?? null,
+        input.status,
+        input.durationMs,
+      )
+      upsertDaily.run(
+        ts,
+        input.account.name,
+        input.modelId,
+        input.endpoint,
+        input.usage.inputTokens,
+        input.usage.cachedInputTokens,
+        input.usage.outputTokens,
+        input.usage.reasoningTokens,
+        input.usage.totalTokens,
+        premiumRequestCount,
+      )
+    })
+    tx()
+  } catch (err) {
+    consola.error("[usage-recorder] failed to record usage:", err)
+  }
+}
diff --git a/tests/usage-recorder.test.ts b/tests/usage-recorder.test.ts
new file mode 100644
index 00000000..0bed7425
--- /dev/null
+++ b/tests/usage-recorder.test.ts
@@ -0,0 +1,132 @@
+import { test, expect, describe, beforeEach } from "bun:test"
+
+import type { Account } from "../src/lib/account-pool"
+
+import { __resetDbForTests, initDb } from "../src/lib/db"
+import { recordUsage } from "../src/lib/usage-recorder"
+
+const ACCOUNT: Account = {
+  name: "alice",
+  accountType: "individual",
+  githubToken: "ghu_a",
+  copilotToken: "tok_a",
+  copilotTokenRefreshAt: 0,
+  inFlight: 0,
+  lastUsedAt: 0,
+  failureCount: 0,
+}
+
+const baseInput = {
+  account: ACCOUNT,
+  modelId: "gpt-4o",
+  endpoint: "chat.completions" as const,
+  upstreamFormat: "openai" as const,
+  isStreaming: false,
+  usage: {
+    inputTokens: 100,
+    cachedInputTokens: 20,
+    outputTokens: 50,
+    reasoningTokens: 0,
+    totalTokens: 150,
+  },
+  durationMs: 123,
+  status: "ok" as const,
+}
+
+function setupDb() {
+  __resetDbForTests()
+  const db = initDb(":memory:")
+  db.run(
+    "INSERT INTO accounts (name, account_type, created_at) VALUES (?, ?, ?)",
+    [ACCOUNT.name, ACCOUNT.accountType, Date.now()],
+  )
+  return db
+}
+
+describe("recordUsage", () => {
+  beforeEach(() => {
+    __resetDbForTests()
+  })
+
+  test("inserts an event and a daily row", () => {
+    const db = setupDb()
+    db.run(
+      `INSERT INTO model_pricing (
+         model_id, input_per_mtok, cached_input_per_mtok, output_per_mtok,
+         reasoning_per_mtok, premium_multiplier, premium_unit_price,
+         updated_at
+       ) VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
+      ["gpt-4o", 5, 1, 15, 0, 1.0, 0.04, Date.now()],
+    )
+    recordUsage(baseInput)
+
+    const events = db.query("SELECT * FROM usage_events").all() as Array<{
+      account_name: string
+      model_id: string
+      input_tokens: number
+      input_price_snapshot: number
+      premium_request_count: number
+    }>
+    expect(events).toHaveLength(1)
+    expect(events[0].account_name).toBe("alice")
+    expect(events[0].input_price_snapshot).toBe(5)
+    expect(events[0].premium_request_count).toBe(1)
+
+    const daily = db.query("SELECT * FROM usage_daily").all() as Array<{
+      req_count: number
+      input_tokens: number
+      premium_requests: number
+    }>
+    expect(daily).toHaveLength(1)
+    expect(daily[0].req_count).toBe(1)
+    expect(daily[0].input_tokens).toBe(100)
+    expect(daily[0].premium_requests).toBe(1)
+  })
+
+  test("second insert into same (day,account,model,endpoint) increments daily", () => {
+    const db = setupDb()
+    recordUsage(baseInput)
+    recordUsage(baseInput)
+    const daily = db
+      .query<
+        { req_count: number; input_tokens: number },
+        []
+      >("SELECT req_count, input_tokens FROM usage_daily")
+      .all()
+    expect(daily).toHaveLength(1)
+    expect(daily[0].req_count).toBe(2)
+    expect(daily[0].input_tokens).toBe(200)
+  })
+
+  test("missing model_pricing row -> snapshots null and no throw", () => {
+    const db = setupDb()
+    recordUsage(baseInput)
+    const ev = db
+      .query<
+        { input_price_snapshot: number | null; premium_request_count: number },
+        []
+      >("SELECT input_price_snapshot, premium_request_count FROM usage_events")
+      .get()
+    expect(ev?.input_price_snapshot).toBeNull()
+    expect(ev?.premium_request_count).toBe(0)
+  })
+
+  test("isInternal=true inserts nothing", () => {
+    const db = setupDb()
+    recordUsage({ ...baseInput, isInternal: true })
+    const events = db.query("SELECT * FROM usage_events").all()
+    expect(events).toHaveLength(0)
+  })
+
+  test("recorder errors are swallowed", () => {
+    setupDb()
+    // Force an error by passing an invalid endpoint type via cast.
+    expect(() =>
+      recordUsage({
+        ...baseInput,
+        // @ts-expect-error intentional bad value to trigger SQL CHECK fail (none here, but recorder must not throw on weird input)
+        endpoint: undefined,
+      }),
+    ).not.toThrow()
+  })
+})