Overview
What MailerSend is
MailerSend is an email delivery service that sends transactional and marketing email through a simple API, with sending domains, analytics, and deliverability tooling.
Courier sits in front of it as one API, a visual editor, journeys, and every other channel, so you keep MailerSend for delivery and build multi-channel notifications on top.
You need a Courier account and your own MailerSend account with an API token and a verified From Address.
Why Courier
What you get with MailerSend + Courier
Design beautiful emails, no code
Build and edit email in Courier's visual editor. Product and marketing change content and layout without shipping code.
Automate multi-step journeys
Onboarding, drip, and lifecycle sequences with delays and branching, all delivered through MailerSend.
Add SMS, push, and chat
The same notification can reach every channel. Add one when you need it, no new integration in your code.
Add an in-app inbox
A new, easy add-on: drop Courier Inbox into your web or mobile app so users get an in-product notification center alongside email.
Localize a template in seconds
Pick a language and let Courier translate the whole template with AI, then tweak any string. One template, every market.
Send to lists and audiences
Broadcast a one-off or recurring message to an entire list through MailerSend, alongside your transactional email.
Use cases
What teams build with it
Setup
Connect it in minutes
An admin adds MailerSend once on the Integrations page in Courier. Once connected, anyone on your team can design and send email through MailerSend, and add channels whenever they need them.
FAQ
Frequently asked questions
Can I use MailerSend with Courier?
Yes. MailerSend is a supported transactional email provider in Courier. You keep MailerSend for email delivery, and Courier routes your email through it via the Send API while adding content design, Journeys, and other channels on one integration.
Do I still need my own MailerSend account?
Yes. Courier delivers through your own MailerSend account, so you need a verified one with your sending domain added and DNS verification completed in MailerSend before any email will send.
What do I need to connect MailerSend to Courier?
Your MailerSend API token and a From Address. On Courier's MailerSend integration page, enter the API token and From Address, then click Save. That is all Courier needs to start sending email.
Why does my MailerSend email fail with a domain mismatch?
The From Address domain must match the domain the MailerSend API token was generated from. Generate the token in that domain's MailerSend settings, otherwise MailerSend rejects the send.
How do I send attachments or override settings per message with MailerSend?
Use the providers.mailersend.override object on the send. It overrides MailerSend configuration and adds attachments, whose file content must be base64-encoded. MailerSend restricts supported file types, so check its API docs.
How does Courier know which address to send the MailerSend email to?
Courier uses the email field on the recipient's profile, for example email set to alice@acme.com. Include it in the send or store it on the profile; without an email address, delivery is skipped.
Is Courier a replacement for MailerSend?
No. Courier sits in front of MailerSend, which still delivers your email. Courier adds the Send API, Journeys, and Design Studio, plus SMS, push, and Courier Inbox, so one integration drives every channel.
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