Knock
Notification infrastructure with workflow engine.
Knock is a workflow-based notification platform: define workflows in code or visually, route across channels (email, push, SMS, in-app), and let users manage preferences. Email is delivered via your provider of choice.
Judged purely as an API. What the request contract guarantees on retry, how complete the webhook event coverage is, whether suppressions are readable and writable programmatically, and how much the message log retains when something needs debugging in production.
Against high-frequency programmatic sends where a missed delivery is a product failure, Knock covers idempotency keys, webhook coverage, event stream, the suppressions API, batch sending, and SDK breadth, and does not cover operating track record. Whether that gap matters depends on how central those are to the build.
- Idempotency keys: Yes
- Webhooks: Yes
- Event stream: Yes
- Operating since: 2021
- Suppressions API: Yes
- Best published rate per 1,000: Tiers not published in comparable form
- Batch sending: Yes
- SDKs: node, python, go, ruby, php, elixir, java, dotnet
- Deliverability: Inherits the deliverability of the provider you BYO (Postmark, SendGrid, Resend).
Inherits the deliverability of the provider you BYO (Postmark, SendGrid, Resend).
Teams that need multi-channel product notifications with preferences.
- › Strong workflow engine
- › In-app feed component
- › Deep SDK coverage
- › Idempotency keys
- › Pricier than running your own; entry plan is steep
- › Bring your own delivery provider
Features at a glance
| API | Yes |
| SMTP | No |
| SDKs | node, python, go, ruby, php, elixir, java, dotnet |
| Webhooks | Yes |
| Templates | rich |
| React Email | Yes |
| Batch send | Yes |
| Scheduled send | Yes |
| Suppressions | Yes |
| Multi-tenant | Yes |
| Inbound parsing | No |
| Event stream | Yes |
| Idempotency keys | Yes |
| Dedicated IP | No |