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For developers

Email you can
wire into your app.

A REST API for lists, subscribers and campaigns. A transactional API for OTP codes and notifications. Webhooks from automations. Delivery through the provider you choose.

REST API · Transactional API · Webhooks · SMTP and providers

REST API

Lists, subscribers, campaigns and more, with JSON responses.

Transactional API

OTP and notification emails from templates, one call each.

Webhooks

Automations can call your endpoint at any step.

Transactional API

One call per email,
from a template.

POST to /utility/v1/send with a template key, a recipient and the variables for your {{placeholders}}. Authenticate with its own X-API-Key. Sends use a dedicated priority lane, separate from the campaign queue. See Transactional Email for the full reference.

Separate X-API-KeyIts own key, apart from your account API token.
Templates by APIList and create templates at /utility/v1/templates.
Open trackingEvery email gets a tracking pixel, and opens appear on the Logs page.
An API request that sends a one-time password email from a saved template, and the email the customer receives.

Webhooks

Let automations
call your code.

Add a webhook action to an automation and Flashmail calls your endpoint when a subscriber reaches that step. Automations can also start from an API event your app sends. See Automation for every trigger and action.

Webhook actionCall your endpoint from any step of a workflow.
API event triggerStart a workflow from an event your app sends.
Conditions and waitsBranch on attributes, tags or activity, and wait between steps.
A welcome automation: when someone subscribes, wait one day, send a welcome email, then branch on whether it was opened.

What you get

The building blocks for email in your product.

JSON in, JSON out.

REST API

Base URL api.flashmail.id/api/v1, Bearer token or api_token parameter.

Subscriber endpoints

List, add, update and tag subscribers.

Campaign endpoints

Work with campaigns from your code.

Transactional API

Templates with {{variables}}, sent through a priority lane.

Webhooks

Called from automation steps.

Delivery providers

Pick the provider or SMTP server that sends your email.

Delivery

Choose how
your email is sent.

Supported delivery providers include Amazon SES, SendGrid, Mailgun, Elastic Email, SparkPost, Blastengine, generic SMTP and Gmail (OAuth). Verify your sending domain with SPF, DKIM and DMARC.

Delivery providersAmazon SES, SendGrid, Mailgun, SparkPost and others.
Generic SMTPConnect any SMTP server you already use.
Domain authenticationSPF, DKIM and DMARC records for your sending domain.

Getting started

Send your first email from code.

Get a key, create a template, make a request.

  1. 1

    Get your keys

    Copy the API token from Account → API, and your X-API-Key for transactional sends.

  2. 2

    Create a template

    Add a template key, subject and HTML body with {{variables}}.

  3. 3

    Make a request

    POST the template key, recipient and variables to send.

Common questions.

What does an API response look like?

Responses are JSON with a status, a message and a data field, for example {"status":1,"message":"Success","data":…}.

Do transactional emails wait behind campaigns?

No. Transactional sends go through a dedicated priority lane, separate from the campaign sending queue.

Is the transactional API on every plan?

Access to the Email Utility API depends on your plan. The REST API uses the token from Account → API.

Ship email features
without building a mail system.

Create a free account and get your API token.