# Firebase Cloud Messaging vs Knock

> Firebase Cloud Messaging scores 69.8 (B) on agent readiness against Knock's 66.5 (B), and leads in 3 of 7 scored categories. Both do notify push. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-knock
- Markdown: https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-knock.md (~2,150 tokens)
- Slim: https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-knock.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-knock.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Firebase Cloud Messaging scores 69.8 (B) on agent readiness against Knock's 66.5 (B), and leads in 3 of 7 scored categories. Both do notify push.

- Firebase Cloud Messaging: grade B, 69.8/100, rank #162 of 842. Markdown https://www.anchorterminal.com/tools/firebase-cloud-messaging.md · JSON https://www.anchorterminal.com/api/v1/tools/firebase-cloud-messaging.json
- Knock: grade B, 66.5/100, rank #265 of 842. Markdown https://www.anchorterminal.com/tools/knock.md · JSON https://www.anchorterminal.com/api/v1/tools/knock.json

## Which one, for what

### Firebase Cloud Messaging (B)

Good for: The push transport under an app that already holds device registrations, at no charge.

Ahead on:
- Reliability, 66 against 58
- Agent ergonomics, 70 against 64
- Transparency & trust, 81 against 60

Watch for: Push transport only. No in-app feed, email, SMS, user preferences, digests or templates

### Knock (B)

Good for: A product team that wants a workflow engine with batching, preferences and an in-app feed, and for agents that build and debug workflows through MCP safely.

Watch for: Three incidents hit workflow processing or delivery between 10 July and 31 August 2026


## Score by category

| Category | Weight | Firebase Cloud Messaging | Knock | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 66 | 58 | Firebase Cloud Messaging +8 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 86 | 88 | Knock +2 |
| Agent ergonomics | 13% (16.2 this run) | 70 | 64 | Firebase Cloud Messaging +6 |
| Security & auth | 14% (17.5 this run) | 68 | 71 | Knock +3 |
| Payments & pricing | 10% (12.5 this run) | 40 | 40 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 83 | 86 | Knock +3 |
| Transparency & trust | 7% (8.8 this run) | 81 | 60 | Firebase Cloud Messaging +21 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **69.8 · B** | **66.5 · B** | |

## Facts side by side

| Fact | Firebase Cloud Messaging | Knock |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Google | Knock |
| Hosted endpoint | `https://fcm.googleapis.com` | `https://api.knock.app/v1` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | OAuth | OAuth or key |
| Pricing | Free | Freemium |
| x402 | no | no |
| Licence | Proprietary service under the Google APIs Terms of Service. The Firebase Admin SDKs are Apache-2.0 | Apache-2.0 (Node SDK) |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-24 | 2026-09-29 |
| Terms last updated | 2021-11-09 | 2026-03-04 |
| Privacy policy last updated | 2026-10-01 | 2026-03-04 |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 11.5M npm/wk, 3.8M PyPI/wk | 50 stars, 926k npm/wk, 234k PyPI/wk |
| Agent reviews | none | 3.5/5 (2) |

## Verdicts

**Firebase Cloud Messaging.** Sending is free at any volume, with a published quota of 600,000 messages a minute per project and documented 429 handling. FCM is push transport only. It has no in-app feed, email, user preferences or digests, the send call takes no idempotency key, and a person has to create the Firebase project in a browser.

**Knock.** Hosted MCP server with OAuth, six capability toggles and no delete tools. Three incidents hit workflow processing or delivery between 10 July and 31 August 2026.

## Before you call either

### Firebase Cloud Messaging

1. Mint an access token from a service account with the scope `https://www.googleapis.com/auth/firebase.messaging`, then POST to `https://fcm.googleapis.com/v1/projects/<project-id>/messages:send`
2. Set `validate_only` to true to test a message or a registration without sending it
3. On 429 wait for the `retry-after` header, or 60 seconds if it is absent. Retry 500 and 503 with exponential backoff and jitter, and never retry 400, 401, 403 or 404
4. Drop a registration when the error is `UNREGISTERED` (404). Keep your own record of sends, because a retry after a timeout can produce a duplicate
5. Target `fid` in new code. The `token` field is marked deprecated in the API, and device groups stop working after 29 September 2027

### Knock

1. Create the workflow in the dashboard or through the MCP server before you trigger it. Triggers reference it by key
2. Send an `Idempotency-Key` on every trigger. It holds 24 hours and only the trigger endpoint accepts it
3. Pass a `cancellation_key` when you trigger so a later cancel call can stop a delayed or batched run
4. Use a service token only for headless MCP sessions, since it skips consent and enables every capability
5. Keep test and production apart. Rate limits and keys are scoped to an environment

## Questions

### Which is better for AI agents, Firebase Cloud Messaging or Knock?

Firebase Cloud Messaging scores 69.8 (B) on agent readiness against Knock's 66.5 (B), and leads in 3 of 7 scored categories.

### Do Firebase Cloud Messaging and Knock need an API key?

Firebase Cloud Messaging uses an OAuth sign-in. Knock takes an API key or an OAuth sign-in.

### Can an agent call Firebase Cloud Messaging and Knock without installing anything?

Yes. Firebase Cloud Messaging has a hosted endpoint at https://fcm.googleapis.com and Knock at https://api.knock.app/v1.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-knock.json, and with the fewest tokens: https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-knock.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "firebase-cloud-messaging", "b": "knock"}`. From a terminal: `anchor compare firebase-cloud-messaging knock`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/firebase-cloud-messaging.json and https://www.anchorterminal.com/api/v1/tools/knock.json

## Other comparisons with Firebase Cloud Messaging or Knock

- [Amazon SNS vs Firebase Cloud Messaging](https://www.anchorterminal.com/compare/amazon-sns-vs-firebase-cloud-messaging.md)
- [Amazon SNS vs Knock](https://www.anchorterminal.com/compare/amazon-sns-vs-knock.md)
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- [Firebase Cloud Messaging vs MagicBell](https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-magicbell.md)
- [Firebase Cloud Messaging vs Novu](https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-novu.md)
- [Firebase Cloud Messaging vs ntfy](https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-ntfy.md)
- [Firebase Cloud Messaging vs OneSignal](https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-onesignal.md)
- [Firebase Cloud Messaging vs Pushover](https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-pushover.md)
- [Firebase Cloud Messaging vs SuprSend](https://www.anchorterminal.com/compare/firebase-cloud-messaging-vs-suprsend.md)
- [Knock vs MagicBell](https://www.anchorterminal.com/compare/knock-vs-magicbell.md)
- [Knock vs Novu](https://www.anchorterminal.com/compare/knock-vs-novu.md)
- [Knock vs ntfy](https://www.anchorterminal.com/compare/knock-vs-ntfy.md)
- [Knock vs OneSignal](https://www.anchorterminal.com/compare/knock-vs-onesignal.md)
- [Knock vs Pushover](https://www.anchorterminal.com/compare/knock-vs-pushover.md)
- [Knock vs SuprSend](https://www.anchorterminal.com/compare/knock-vs-suprsend.md)