Linje

Product email infrastructure

Transactional email and inbound webhooks.

Send the email your product depends on. Let customers reply normally, then deliver each answer to the right application object. Keep the delivery trail inspectable when something fails.

HTTP to email Email to HTTP Receipts Magic links Replies No campaigns
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Outgoing

Your app sends product email.

Use one API for receipts, magic links, password resets, invites, and alerts.

Your app Linje Recipient inbox 
POST /v1/messages
{
  "from": "auth@tx.example.com",
  "to": ["you@example.com"],
  "subject": "Your sign-in link"
}

Incoming

Incoming email returns to your app.

Use an inbox directly or forward mail into one. Linje sends your endpoint a signed payload with the message and attachments.

Mail Linje inbox Your endpoint 
POST /v1/inboxes

POST https://app.example.com/inbound
{
  "inbound-id": "...",
  "email": {
    "from": [{"email":"user@example.com"}],
    "subject": "Reply"
  },
  "attachments": [...]
}

Replies

A reply returns to the object that sent it.

Generate an opaque Reply-To address with caller metadata. Linje maps the reply back without exposing a business identifier in the address.

Application object Reply address Webhook event 
POST /v1/reply-routes
Idempotency-Key: 018f47d2-89ab-4cde-8123-456789abcdef
{"inbox-id":"orders",
 "metadata":{"order-id":"order_82921"}}

WEBHOOK
"route": {
  "id": "route_...",
  "metadata": {"order-id":"order_82921"}
}

Reliability

The delivery trail is part of the product.

Linje stores the email event before callback delivery and keeps attempts visible when your endpoint or the mail path fails.

Durable history

Inspect message status, delivery attempts, bounces, and webhook responses.

Retry and replay

Automatic backoff handles transient failures. Replay the same event without creating a new email.

Signed artifacts

Verify callbacks with HMAC signatures and retrieve raw messages and attachments through controlled references.

Product boundary

One small service with a clear job.

Linje handles product email in both directions, then gets out of the way. Business workflows stay in your app.

HTTP to email

Send receipts, magic links, password resets, invites, and alerts.

Email to HTTP

Turn inbound email and attachments into signed webhook events.

No ESP creep

No campaigns, lists, open tracking, click tracking, or workflow builder.

Common jobs

Start where email touches your product.

Inbound Email API Receive messages, replies, and attachments inside your application. Transactional Email API Send the product messages users expect to receive. Inbound Email Webhooks Receive email and attachments inside your application. Email to Webhook Turn replies and inbound addresses into application events. Reply by Email API Route customer replies to the right order, ticket, invoice, or application object. Inbound Email for Amazon SES Keep SES for sending and add application-aware replies without assembling the inbound stack. SendGrid Inbound Parse Alternative Keep SendGrid for sending and route replies with managed application context. Mailgun Inbound Email Alternative Compare inbound rules with one managed reply address per application object. Resend Inbound Email Alternative Keep Resend outbound and add explicit metadata and lifecycle to every reply route. Webhook Replay Recover cleanly when a downstream handler was down.

Pricing

Free during preview. Paid plans start at $5/month.

Build and run a real Linje integration without entering payment details. After preview, choose the plan that fits your monthly usage.

Plans count outbound recipient deliveries and accepted inbound emails in one shared monthly allowance. Webhook retries, replay, and stored reply routes do not consume additional usage.

Plan Messages / month Price
Free 500 $0
Growth 5,000 $5/month
Scale 50,000 $25/month