Google Ads & GA4

Local emulators. Real API contracts. Part of Mockingbird.

A wip portable emulator for Google Ads API v25 and Google Analytics 4. It provides deterministic GAQL reporting, campaign-budget mutations, click-conversion uploads, Measurement Protocol event collection, and Analytics Data reports using namespaced SQLite state and an injected clock.

#Install

bun add @crvouga/mockingbird-service-google-ads

#Usage

import { OAuth2Client } from "google-auth-library"
import { DEFAULT_CUSTOMER, DEFAULT_TOKEN } from "@crvouga/mockingbird-service-google-ads"
import { createServer } from "@crvouga/mockingbird-service-google-ads/server"

const emulator = await createServer()

// Google publishes no Node client for the Ads API, so the application calls REST through
// google-auth-library. Only the base URL and the fixture token change.
const client = new OAuth2Client()
client.setCredentials({ access_token: DEFAULT_TOKEN })
const response = await client.request({
  url: `${emulator.url}/v25/customers/${DEFAULT_CUSTOMER}/googleAds:search`,
  method: "POST",
  data: { query: "SELECT campaign.id, campaign.name, metrics.clicks FROM campaign" },
})
console.log(response.data)

await emulator.close()

The Ads and Analytics Data routes use OAuth Bearer credentials. Measurement Protocol routes use the measurement_id and api_secret query parameters. The exported defaults are synthetic and safe for tests. Configure tokens, customers, campaigns, budgets, conversion actions, metrics, and Analytics properties through createRuntime options when a suite needs different fixtures.

For parallel tests, send x-mockingbird-namespace, use the shared /__admin/ns/{namespace} path, or register credentials with the shared admin API. State, pagination snapshots, IDs, clocks, faults, and resets are isolated by namespace.

#Supported operations

The exact request and response schemas are in openapi.yaml, and the generated support matrix is in SUPPORT.md.

Campaign budgets are read back with GAQL (FROM campaign_budget); uploaded conversions and collected events are read through the inspection routes below, and events also through the Analytics Data reports. REST rows use protobuf JSON names (costMicros, conversionsValue, conversionActionCategory) and int64 values are strings; GAQL field names stay snake_case.

Google Ads failures are a google.rpc.Status whose details hold a GoogleAdsFailure with the per-operation errorCode, message, location and a requestId equal to the request-id response header. Unparsable JSON and every Analytics Data failure are a bare status with no Ads detail and no request-id header.

#Where Google differs from a common assumption

These follow Google's documentation and the pinned googleapis v25 protos rather than what a client written against an older contract may expect.

• Search page size is fixed. Search returns pages of up to 10,000 rows and a request that sets pageSize is rejected with requestError: PAGE_SIZE_NOT_SUPPORTED. Continue by re-sending the identical query with pageToken; a changed query is INVALID_PAGE_TOKEN and a token unused for two hours is EXPIRED_PAGE_TOKEN (paging guide, SearchGoogleAdsRequest). To page a small fixture, lower the emulator's page with the searchPageSize setting; the request still cannot choose it.
• /mp/collect never reports validation errors over HTTP. It answers an empty 204 for a bad secret, an unparsable body or a rejected event alike. Inspect a rejection with POST /debug/mp/collect, which returns validationMessages and stores nothing, or with GET /__admin/request-metadata, which records accepted, rejected, duplicate and reasons per request (validation guide).
• Timestamps older than 72 hours are overridden, not rejected, unless the request sets validation_behavior: "ENFORCE_RECOMMENDATIONS" (sending guide). Google documents no bound for future timestamps, so the one-minute futureToleranceMs default is a test policy of this emulator, not a vendor rule; set it to null to disable it.
• A validate-only budget mutation returns errors only. A valid preflight answers {} with no results and writes nothing (MutateCampaignBudgetsRequest).
• Mutations take no idempotency key. The duplicate guards are Google's own: a shared budget name (campaignBudgetError: DUPLICATE_NAME), a conversion orderId (ORDER_ID_ALREADY_IN_USE), a click and conversion time (CLICK_CONVERSION_ALREADY_EXISTS), and a web purchase event's transaction_id per user.
• developer-token is accepted and ignored. The pinned protos mark the developer-token errors as sunset; login-customer-id is still checked against the customer's manager.

#Controls and failures

Service-specific controls are protected by the shared x-mockingbird-admin-key guard and live beside the shared health, state, clock, journal, fault, reset, and Timeline endpoints.

Fault presets are quota_exhausted, rate_limited, server_error, network_reset, slow_response, ambiguous_budget_write, partial_budget_failure, and partial_conversion_failure. Each fires once unless count says otherwise, and is scoped to the calling namespace. The two throttling presets answer 429 RESOURCE_EXHAUSTED with quotaError: RESOURCE_EXHAUSTED or RESOURCE_TEMPORARILY_EXHAUSTED and the backoff in details.quotaErrorDetails.retryDelay, before anything is written.

ambiguous_budget_write commits the next executed budget mutation and then returns 503, so retry logic can be tested against an uncertain outcome. A validate-only preflight executes nothing and does not spend it: the fault waits for the real call that follows. Reconcile before replaying: the 503 carries a request-id header, and GET /__admin/budget-mutations lists the write under that request ID with the budget's before and after.

Sensitive event and conversion payloads are sealed in state; journals and inspection metadata contain only the fields needed for assertions.

#API

The portable root exports GoogleAdsAPI, createRuntime, document, supportedOperationIds, GOOGLE_ADS_NAMESPACE, GOOGLE_ADS_PRESETS, DEFAULT_ADMIN_KEY, DEFAULT_TOKEN, DEFAULT_CUSTOMER, DEFAULT_CUSTOMERS, DEFAULT_BUDGETS, DEFAULT_CAMPAIGNS, DEFAULT_ACTIONS, DEFAULT_PROPERTY, DEFAULT_MEASUREMENT, DEFAULT_API_SECRET, createVaultKey, fingerprint, and the public fixture/runtime option types. The Node ./server entry exports createServer, DEFAULT_PORT, and server types. mockingbird-google-ads serve starts a listener.

#Verification and scope

Acceptance tests cover GAQL precision and paging, budget preflight and partial writes, conversion deduplication, GA4 event validation and reporting, OAuth scope/expiry behavior, encrypted state, namespaces, resets, fault recovery, and the unmodified google-auth-library 11.1.0 HTTP signing path. Runtime tests drive every control above over /__admin. Property tests exercise every parity-enabled operation and prove that a divergent transport is detected deterministically.

test/consumer.ts is a port of the raw-fetch traffic described in the original service request. It is not the requesting application's client, whose source is not in this repository, so no test here runs that client unmodified.

#Deliberately not modelled

The emulator implements a bounded subset. It does not model the complete Google Ads resource graph, every GAQL function, GAQL field-compatibility rules between segments and metrics, every Analytics dimension or metric, real Google identity, production quota allocation, billing, dashboards, attribution processing, or undocumented backend behavior. Uploaded conversions do not feed metrics.conversions; seed those with daily metrics. Normal operation is local and does not contact Google; only the explicit parity command uses credentials supplied through .env.local or GitHub Actions secrets.