# Google Tag Manager

> Google Tag Manager (GTM) is a tag management system that lets you deploy and update measurement codes and related code fragments (tags) on a website, mobile app, or server-side container without editing site code. The Tag Manager API v2 provides programmatic management of accounts, containers, workspaces, tags, triggers, variables, container versions, and user permissions across web, iOS, Android, AMP, and server-side usage contexts.

Generated by the API Evangelist enrichment pipeline from apis.yml + repo artifacts on 2026-08-13. No provider-published llms.txt exists — developers.google.com/llms.txt and developers.google.com/tag-platform/llms.txt both return 404.

## How this API works

- Base URL `https://tagmanager.googleapis.com`, all paths under `/tagmanager/v2`. Single production host; there is no sandbox host and no test mode.
- Auth is **OAuth 2.0 authorization code only** — no API keys. Seven scopes separate read, edit, publish, delete, and user management.
- Resources are addressed by a composite **resource path** (`accounts/{a}/containers/{c}/workspaces/{w}/tags/{t}`) returned by the previous call, not by concatenating ids.
- Writes use **fingerprint-based optimistic concurrency** (a `fingerprint` query parameter), not ETags. There is **no `Idempotency-Key`** — a retried create duplicates.
- Changes stage in a **workspace**, freeze into an immutable **container version**, then **publish** to live traffic. Publishing is the only step that changes what runs on a customer's site.
- Quota is **per Google Cloud project**: 10,000 requests/day and 0.25 QPS (25 per 100s window). Exhaustion returns **HTTP 403** (not 429) with reason `userRateLimitExceeded` or `quotaExceeded`. No rate-limit response headers are emitted.
- Errors use the **Google JSON error envelope** (`error.code` / `error.message` / `error.errors[].reason`), not RFC 9457. Branch on `errors[].reason`; Google states the message text may change at any time.

## APIs

- [Google Tag Manager API v2](https://developers.google.com/tag-platform/tag-manager/api/v2): 44 operations across accounts, containers, workspaces, tags, triggers, variables, versions, and user permissions. Base URL https://tagmanager.googleapis.com
- [Google Tag Manager Server-side Tagging API](https://developers.google.com/tag-platform/tag-manager/server-side): Build custom tags, clients, and variables that run in a server-side container.

## Specs

- [OpenAPI 3.1 — Accounts](openapi/google-tag-manager-accounts-api-openapi.yml)
- [OpenAPI 3.1 — Containers](openapi/google-tag-manager-containers-api-openapi.yml)
- [OpenAPI 3.1 — Workspaces](openapi/google-tag-manager-workspaces-api-openapi.yml)
- [OpenAPI 3.1 — Tags](openapi/google-tag-manager-tagmanager-api-openapi.yml)
- [OpenAPI 3.1 — Triggers](openapi/google-tag-manager-triggers-api-openapi.yml)
- [OpenAPI 3.1 — Variables](openapi/google-tag-manager-variables-api-openapi.yml)
- [OpenAPI 3.1 — Versions](openapi/google-tag-manager-versions-api-openapi.yml)
- [OpenAPI 3.1 — User Permissions](openapi/google-tag-manager-user-permissions-api-openapi.yml)
- [Google Discovery Document (upstream source contract, revision 20260812)](openapi/_original/google-tag-manager-tagmanager-v2-discovery.json)
- [JSON Schema (container + 35 entities)](json-schema/)
- [Postman collections](collections/)
- [Arazzo workflows (12)](arazzo/)
- [OpenAPI Overlays (8)](overlays/)
- [Vocabulary](vocabulary/)
- [JSON-LD context](json-ld/)

## Agent surface

- [Agent Skills (6 packaged flows)](skills/_index.yml) — provision, build-and-publish, safe update/revert, live audit + rollback, workspace sync/conflict resolution, user permissions
- [MCP tool candidates (44, derived — Google ships no first-party MCP server)](mcp/google-tag-manager-mcp.yml)
- [MCP tool ↔ OpenAPI operation crosswalk](mcp/google-tag-manager-tool-crosswalk.yml)
- [Agentic access classification](agentic-access/google-tag-manager-agentic-access.yml)
- No A2A agent card: `/.well-known/agent-card.json` and `/.well-known/agent.json` return 404 on every Tag Manager host.

## Operational artifacts

- [Authentication profile](authentication/google-tag-manager-authentication.yml) · [OAuth scopes](scopes/google-tag-manager-scopes.yml)
- [API conventions](conventions/google-tag-manager-conventions.yml) · [Error catalog](errors/google-tag-manager-problem-types.yml)
- [Rate limits](rate-limits/google-tag-manager-rate-limits.yml) · [Plans and pricing](plans/google-tag-manager-plans-pricing.yml)
- [Lifecycle](lifecycle/google-tag-manager-lifecycle.yml) · [Changelog](changelog/google-tag-manager-changelog.yml)
- [Sandbox and test posture](sandbox/google-tag-manager-sandbox.yml) · [Data model](data-model/google-tag-manager-data-model.yml)
- [Client libraries](packages/google-tag-manager-packages.yml) · [Embedded components](components/google-tag-manager-components.yml)
- [Conformance](conformance/google-tag-manager-conformance.yml) · [Trust center / ISO 27001](security/google-tag-manager-trust-center.yml)
- [Domain security](security/google-tag-manager-domain-security.yml) · [Vulnerability disclosure](security/google-tag-manager-vulnerability-disclosure.yml)
- [Well-known probe](well-known/google-tag-manager-well-known.yml)

## Docs

- [Developer guide](https://developers.google.com/tag-platform/tag-manager/api/v2/devguide)
- [REST reference (with embedded "Try it!" APIs Explorer)](https://developers.google.com/tag-platform/tag-manager/api/reference/rest)
- [Authorization / OAuth scopes](https://developers.google.com/tag-platform/tag-manager/api/v2/authorization)
- [Error responses and retry guidance](https://developers.google.com/tag-platform/tag-manager/api/v2/errors)
- [Limits and quotas](https://developers.google.com/tag-platform/tag-manager/api/v2/limits-quotas)
- [Client libraries](https://developers.google.com/tag-platform/tag-manager/api/v2/libraries)
- [Changelog](https://support.google.com/tagmanager/answer/4620708)
- [Server-side release notes](https://developers.google.com/tag-platform/tag-manager/server-side/release-notes)
- [Pricing / compare versions](https://marketingplatform.google.com/about/tag-manager/compare/)
- [ISO 27001 certification](https://support.google.com/marketingplatform/answer/9013962)
- [Vulnerability reward program](https://g.co/vrp)

## Known absences

- No status page or incident dashboard for Tag Manager (status.cloud.google.com covers Google Cloud only and does not list it).
- No published deprecation policy for this API, and no RFC 8594 Sunset/Deprecation response headers.
- No webhooks, no event stream, no AsyncAPI — the API is configuration-only, so there is nothing to subscribe to.
- No published SLA on the free tier.
- No sandbox host, no test-mode credentials, no magic test identifiers. Every call is production, and destructive operations have "no warnings, no confirmations, and no undo."