Posta
What it is
Posta is a free, open-source email delivery platform that runs on infrastructure you control. It sends and receives email through an HTTP API and also supports API sending, SMTP relay, inbound mail, and website form submissions. The REST API handles transactional, batch, and templated messages with attachments, scheduling, retries, and priority queues. Incoming mail can use built-in SMTP with TLS or an authenticated webhook, with forwarding and real-time SSE notifications. Templates support versioning, localization, visual editing, and previews; campaigns add scheduling, A/B testing, and send-rate throttling. Posta supports SMTP providers and SPF, DKIM, and DMARC domain verification. Official SDKs are listed for Go, PHP, Java, and .NET, along with Prometheus and OAuth/SSO integrations. Security controls include hashed keys, JWT authentication, role-based access, two-factor authentication, rate limiting, and session management. It is licensed under AGPL-3.0.
For and against
For
- Free AGPL-3.0 open-source license
- Supports sending, receiving, and SMTP relay
- Templates include versioning and localization
- Provides multiple authentication and security controls
- Offers Docker Compose deployment
Against
- Runs on the customer’s own infrastructure
- Web form messages are disabled by default
- Documented form limits include hourly and daily caps
The verdict
Posta combines outbound delivery, inbound handling, templates, campaigns, and event webhooks in a self-hosted package. Its open-source license and deployment control suit teams prepared to manage infrastructure and usage limits.
Who it suits
Posta suits teams wanting self-hosted email delivery, inbound mail, templates, and webhooks. It is available through web, API, and self-hosted deployment.
Plans and prices
Self-hosted, AGPL-3.0
Free and open source · runs on your own infrastructure; no published usage limits
Read 8 Oct 2026 · goposta.dev
On the record
- Data controls
- Posta describes isolated workspaces and provides data export, import, and GDPR deletion tools.goposta.dev · read 8 Oct 2026
- Delivery methods
- bothgithub.com · read 20 Sep 2026
- Deployment
- Posta is self-hosted on the customer’s infrastructure and the maker provides a Docker Compose startup option.goposta.dev · read 8 Oct 2026
- Email delivery
- The REST API supports transactional, batch, and templated sends, attachments, scheduled sending, retries, and priority queues.goposta.dev · read 8 Oct 2026
- Event webhooks
- Yesgithub.com · read 20 Sep 2026
- Form messages limit
- Web form messages are disabled by default; the documented default limits include 200 submissions per form per hour and 1,000 per workspace per day.docs.goposta.dev · read 8 Oct 2026
- Inbound email
- Posta can receive inbound mail through built-in SMTP with TLS or an authenticated webhook, and supports forwarding and real-time SSE notifications.goposta.dev · read 8 Oct 2026
- Integrations
- The maker lists official SDKs for Go, PHP, Java, and .NET, plus Prometheus integration and OAuth/SSO providers including Google, Keycloak, and authentik.goposta.dev · read 8 Oct 2026
- License
- The maker identifies Posta as free and open source under AGPL-3.0.goposta.dev · read 8 Oct 2026
- Security
- Listed security features include hashed API keys, optional key expiration and IP allowlists, JWT authentication, role-based access, two-factor authentication, rate limiting, and session management.goposta.dev · read 8 Oct 2026
- SMTP and domain setup
- Posta supports multiple SMTP providers and domain verification with SPF, DKIM, and DMARC.goposta.dev · read 8 Oct 2026
- Template options
- bothgithub.com · read 20 Sep 2026
- Templates and campaigns
- Templates support versioning, localization, visual editing, and preview; campaigns support scheduled delivery, A/B testing, and send-rate throttling.goposta.dev · read 8 Oct 2026
- Ways to use it
- It supports API sending, SMTP relay, inbound email, and website form submissions.goposta.dev · read 8 Oct 2026
- Webhooks
- Webhooks support event filters, HMAC signing, retries, and delivery tracking.goposta.dev · read 8 Oct 2026
- What it does
- Posta is a self-hosted email delivery platform for sending and receiving email through an HTTP API.goposta.dev · read 8 Oct 2026
