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.
A SaaS product sends on behalf of its customers, so the deciding factors are tenant isolation, whether suppressions can be scoped rather than global, and whether support can answer why one specific account did not receive one specific email. Lifecycle automation and transactional sending usually need to coexist.
Against trial expiry notices, dunning, onboarding sequences, and per-tenant transactional mail, Knock covers multi-tenant support, event stream, the suppressions API, scheduling, and webhook coverage, and does not cover operating track record. Whether that gap matters depends on how central those are to the build.
- Multi-tenant: Yes
- Event stream: Yes
- Suppressions API: Yes
- Operating since: 2021
- Scheduling: Yes
- Best published rate per 1,000: Tiers not published in comparable form
- Deliverability: Inherits the deliverability of the provider you BYO (Postmark, SendGrid, Resend).
- Webhooks: Yes
- Starts at: $249/mo (Starter)
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 |