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Envoi

Transactional email on your own domain.

Envoi is a transactional email platform for teams who want to own their deliverability story. Bring your domain, get a DKIM keypair in seconds, write templates in Handlebars, and send through a single REST endpoint. Bounces feed a per-team suppression list automatically.

Every “just send email” tool lands in the same place: a relay that hides your signing story, a dashboard that doesn't know about your team structure, and a bill that punishes growth. Envoi inverts that. The DKIM key is on your domain. The suppression list is yours. The template registry belongs to the team that wrote it.

Multi-tenant inside your own app? Envoi rides on Heimdall's tenancy primitives. Your customers' teams are real teams in our system — scoped keys, scoped domains, scoped rate limits.

Get startedOpen in console

Capabilities

Core features

Custom domains

Send from and receive at any domain you own. Envoi generates a per-domain DKIM keypair, gives you the DNS records to set, and verifies ownership via a TXT challenge.

Templates

Handlebars templates stored server-side. Render with a data payload, preview before you send, version with your git history. Subject, HTML, and plain-text are all templated.

Scoped API keys

Mint hdk_live_* keys with a permission set — message.send, template.create, domain.read, etc. Keys are tenancy-scoped so a staging key can’t touch production data.

Multi-team

Organise domains, templates, and keys into teams. Invite teammates, assign roles (owner / admin / member). Each team gets its own suppression list and rate limits.

Suppression list

Permanent 5xx bounces auto-populate a per-team blocklist. Sends to suppressed addresses return 422 before they hit your queue. Manage manually or let it self-populate.

Inbound webhook-ready

Receive mail at any of your verified domains. Every message is stored with parsed MIME, attachments content-addressed, and full SPF / DKIM / DMARC auth results.

Integration

How it works

Three steps from zero to a signed email landing in a real inbox.

1

Register and verify a domain

POST your fqdn; we generate a DKIM keypair and hand back the DNS records (MX, SPF, DKIM, verification TXT). Set them, then call verify.

POST /v1/apps/:appId/tenancies/:teamId/domains
{ "fqdn": "acme.com" }
2

Create a template

Handlebars subject + HTML + optional plain-text body. Render previews before sending.

POST /v1/apps/:appId/tenancies/:teamId/templates
{
  "name": "welcome",
  "subject": "Welcome, {{name}}",
  "bodyHtml": "<h1>Hi {{name}}</h1><p>Thanks for signing up.</p>"
}
3

Send it

One HTTP call. Render + DKIM-sign + queue + deliver. Returns 202 Accepted once queued.

POST /…/templates/welcome/send
Authorization: Bearer hdk_live_...

{
  "from": "hello@acme.com",
  "to": "user@example.com",
  "data": { "name": "Alice" }
}

Under the hood

Technical details

REST-first

No SDK required. curl, fetch, any HTTP client. Every operation is a JSON POST / GET. OpenAPI spec at /docs on the API.

DKIM + SPF + DMARC

Outbound DKIM-signed per domain with a key you control. Inbound checks all three protocols via mailauth on every received message.

Rate-limited by design

Per-team sliding-window limits on outbound (60/min, 600/hr, 10k/day default). Per-caller limits on verification-email resends. Clean 429 responses.

DKIM keys encrypted at rest

Private keys are stored AES-256-GCM envelope-encrypted with a cluster-managed master key. Rotation is a documented procedure, not a migration.

Dogfooded

ProductCraft uses Envoi for every transactional email across our own products. The problems we hit show up in the roadmap first.

Send your first email

The getting-started guide walks through domain verification, DNS records, template authoring, and your first send — all with copy-paste curl commands.

Read the guideOpen in console