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.
An agent stack treats email as a two-way primitive. Inbound has to arrive as structured JSON a tool call can consume, sends have to be safe to retry when a model loop repeats itself, and every action needs an audit trail. A provider without inbound parsing only solves half the problem.
Against inbound parsing into tool calls and model-generated sends that must not duplicate, Knock covers idempotency keys, webhook coverage, event stream, batch sending, SDK breadth, and multi-tenant support, and does not cover inbound parsing and operating track record. Whether that gap matters depends on how central those are to the build.
- Inbound parsing: No
- Idempotency keys: Yes
- Webhooks: Yes
- Operating since: 2021
- Event stream: 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
- Multi-tenant: Yes
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 |