How do I send an email from Elixir?

POST JSON to https://sendandretain.com/api/v1/emails with your aem_ key as a Bearer token. Req or Finch is enough, and the call returns 202 with a message ID.

Do I need an Elixir SDK?

No. Req, Finch, and other BEAM HTTP clients call the API directly, so pooling, telemetry, and supervision stay in your app.

How do Oban retries avoid duplicate email?

Derive one stable Idempotency-Key from the email and reuse it on every attempt. A retried job then points at the same send instead of queuing another.

Does a 202 response mean the email was delivered?

No. It means the email passed the send checks and is queued. Keep the returned ID and read the outcome from your signed webhook or the message log.

Can I send marketing emails from Elixir?

Yes, through automations. Send product events from your app, and automations you've turned on send the welcome, trial, or win-back emails. There are no newsletter blasts; every email goes to one person.

Send emails from Elixir

Transactional and marketing email from Elixir apps and Oban jobs. One Req call, and a message ID you can follow to the inbox.

Start for free Read the API reference

✓Free to start. Unlimited contacts on every tier.

Server quickstart

Elixir

One request, complete trace

Request

POST /api/v1/emails

Authorization: Bearer aem_…

Idempotency-Key: welcome-8f21

{ "to": "[email protected]", "template": "welcome" }

202 Accepted

{ "id": "msg_7ca31", "status": "queued" }

RuntimeServer process

RequestPOST /api/v1/emails

Result202 · queued

Credentials stay server-sideInspect

[ 01 / 04 ]Quickstart

How do I send email from Elixir?

Three steps from no account to a queued email. No Hex package needed.

Create an API key
In the dashboard, open Settings → API & MCP and create a key with the Send + manage permission (the default). It starts with aem_ and is shown once.
2
Store it as an environment variable
Keep the key on your server. Your code reads it with System.fetch_env!("AEM_KEY").
Terminal
export AEM_KEY="aem_..."

Send the email

POST the recipient and a published template. Req doesn't raise on a 4xx or 5xx, so match on the status. A retry with the same Idempotency-Key won't send a second email.

lib/app/email.ex

response =
  Req.post!("https://sendandretain.com/api/v1/emails",
    headers: [
      authorization: "Bearer #{System.fetch_env!("AEM_KEY")}",
      idempotency_key: "welcome-#{user.id}"
    ],
    json: %{to: user.email, template: "welcome"}
  )

case response do
  %{status: status, body: body} when status in 200..299 -> {:ok, body["id"]}
  %{status: status, body: body} -> {:error, {status, body}}
end

4
Keep the message ID
A 202 means queued, not delivered. Store the id; delivery, bounce, and complaint events arrive later on your signed webhook.
202 Accepted
{ "id": "msg_7ca31", "status": "queued" }

[ 02 / 04 ]In production

What does a production Elixir integration need?

A context around the call

Wrap the request in one context with the endpoint, key, timeout, and error handling. Req and Finch both work.

Oban retries with the same key

Derive one Idempotency-Key per email and reuse it on every attempt, so a retried job never sends twice.

Webhooks checked on the raw body

Cache the raw body in a custom Plug body reader; Plug.Parsers consumes it otherwise.

Events for marketing email

Send product events like signup or trial started. Automations you've turned on decide which email goes out.

[ 03 / 04 ]Example prompts

What can you ask your coding agent to do in Elixir?

Paste these into Claude Code, Cursor, or Codex. Connect the MCP server and it can build the templates and automations too.

Welcome email
“Add an Emails context that sends a welcome email through the Send & Retain API with Req, using the user ID as the idempotency key.”
Oban
“Move our email sends into an Oban worker that reuses the same Idempotency-Key on every attempt and discards 4xx errors instead of retrying.”
Webhooks
“Add a Phoenix endpoint that caches the raw body, verifies Send & Retain webhook signatures, and flags bounced addresses on our users.”
Trial automation
“Send a trial_started event to Send & Retain when a trial begins, then build a paused trial automation for it.”

[ 04 / 04 ]Related

Questions people ask us

Everything else is in the docs.

Send your first email from Elixir.

Create a key, make one call, and follow the message ID to the inbox.

Start for free Read the API reference

Send emails from Elixir

How do I send email from Elixir?

Create an API key

Store it as an environment variable

Send the email

Keep the message ID

What does a production Elixir integration need?

A context around the call

Oban retries with the same key

Webhooks checked on the raw body

Events for marketing email

What can you ask your coding agent to do in Elixir?

More ways to send email from Elixir

Phoenix

Email API

Transactional email

Questions people ask us

Send your first email from Elixir.