Outpost Relay

The problem

Almost every application needs to send email — welcome messages, password resets, invoices, alerts. The default answer is a SaaS provider: per-email pricing that scales against you, your users' data held by a vendor, and an integration you can never leave. Like billing software, delivery infrastructure is something teams rent forever for a need that never changes.

The approach

Outpost Relay is an open-source alternative to SendGrid and FormSubmit that runs on your own infrastructure. Applications call one endpoint — POST /api/v1/send — and the platform handles everything behind it:

• Queue-backed delivery. Every email goes through a Redis-backed job queue with configurable retries and exponential backoff — no dropped messages.
• Native multi-tenancy. Multiple teams or applications on one deployment, each with isolated API keys, templates, logs, and per-tenant SMTP override.
• Provider-agnostic. Any SMTP server, SendGrid, or AWS SES — switchable via a single variable, so there is no lock-in even at the provider layer.
• Operable by design. Searchable delivery logs, HMAC-signed webhooks for real-time delivery events, Handlebars templates managed via API, and a built-in dashboard.

Security at every layer

The lab's security practice shows in the details: API keys hashed with HMAC-SHA256 and never stored in plaintext, SMTP credentials AES-256-GCM encrypted at rest, constant-time key comparison against timing attacks, per-key rate limiting, structured logs that auto-redact secrets, and containers that run as a non-root user.

Status

In active development at Mannat AI Labs — TypeScript throughout (Fastify, Next.js, PostgreSQL, Redis), MIT licensed, built Docker-first for self-hosting. It already powers delivery for the lab's own products as its first production tenant.