The transactional email API that keeps working when your users and AI agents send.

MailChannels Email API sends your app’s email: sign-in links, receipts, notifications. When your users and AI agents start sending through it, each one gets its own sub-account, so one bad sender stops alone.

Start free Move one workflow to us

Your first sendIllustrative

const mail = new MailChannels(apiKey);await mail.send({  from: "hello@yourapp.com",  to: "ada@example.com",  subject: "Your sign-in link",  html: signInEmail(user),});

Illustrative sample. The docs have the exact SDK, endpoint and SMTP settings.

Ada’s inboxIllustrative

Your appJust nowhello@yourapp.com to ada@example.com

Your sign-in link

Hi Ada, here is the link you asked for. Open it on this device to sign in to Your app.

DeliveredA signed webhook tells your app what happened.

Senders on your account

Your app
Customer A
Tenant
AI agentsuspended

Only the AI agent is suspended. Everyone else keeps delivering.

100 free emails a day
SDKs for JavaScript, Python and PHP
Laravel, Symfony and Nodemailer transports
REST API and SMTP

Every app needs email that arrives

Sign-in links, password resets, receipts, notifications: email is a distraction from your product until it breaks. And more apps now send email that their users or AI agents wrote, while the app still carries the reputation.

What your app sends, Written by, Whose reputation
What your app sends	Written by	Whose reputation
Your sign-in linkWritten by: Your app	Your app	Yours
Reset your passwordWritten by: Your app	Your app	Yours
Your receiptWritten by: Your app	Your app	Yours
New comment on your postWritten by: Your app	Your app	Yours
A newsletter a customer wroteWritten by: Your user	Your user	Yours
A follow-up an agent draftedWritten by: An AI agent	An AI agent	Yours

Whose reputation, on every oneYours

How email gets sent today, and where it breaks

Teams start with what is already there, then move to an API built for one company sending its own mail. Platforms often let their users bring their own credentials.

Your server’s mail function or a Gmail account
How it’s solved today
A new app needs email today, so the developer uses what is already there.
Where it falls short
Homegrown sending lands in spam and fails silently.
A generic email API
How it’s solved today
Built for one company sending its own mail. It works well for that.
Where it falls short
Until your users start sending. One bad user can get the whole account suspended, content categories get refused, and abuse handling becomes your job.
Bring-your-own SMTP
How it’s solved today
Platforms let users connect their own SMTP server or Gmail account.
Where it falls short
Provider limits, authentication changes, blocked ports, support tickets, and no visibility into what happened.

And switching providers at that moment is painful.

Add email once. Keep it when your app becomes a platform.

In a perfect world, you or your coding agent add email in minutes, see what happened to every message, and never have to switch providers when your app becomes a platform, because each user, tenant or agent can already send in isolation.

Day one
You, or your coding agent, add email in minutes
An SDK, a framework transport or SMTP settings, and your app is sending.
send("Your sign-in link")
Every message
See what happened to every message
Signed webhooks report each delivery. Addresses that bounce are suppressed for you.
DeliveredBouncedSuppressed
When users and agents send
Each sender is already isolated
Every user, tenant or agent gets its own sub-account. Same API, no migration.
UserTenantAI agent

Meet MailChannels Email API

A transactional email API that sends your app’s email today, and keeps working when your users and AI agents start sending through it.

What it does, in order

Send in minutes, and know it arrived
REST or SMTP, SDKs and framework transports, signed webhooks, a free plan, and docs your coding agent can follow.
Keep working as users and agents send
Sub-accounts with their own credentials, limits and suspension path, plus Domain Lockdown and behavior-based policy.
Deliverability you never run yourself
24/7 abuse operations from a company that has delivered email for web hosting providers for twenty years.

Send your app’s email in minutes, and know it arrived

REST or SMTP, SDKs and framework transports, signed webhooks, a free plan, and docs your coding agent can follow.

What happened to each messageIllustrative

ada@example.comYour sign-in linkDelivered
sam@example.orgYour receiptDelivered
old-address@example.netReset your passwordBounced
old-address@example.netNot sent again: the address bouncedSuppressed

Each event reaches your app as a signed webhook.

REST API and SMTP
The API for new code, SMTP for anything that already sends mail.
Official SDKs
JavaScript, Python and PHP.
Framework transports
Laravel, Symfony and Nodemailer.
Signed delivery webhooks
Know what happened to every message.
Automatic suppression
Bounced addresses stop receiving mail.
DKIM and Domain Lockdown
Only the accounts you authorize may send for your domain.
Docs a coding agent can follow
Agent plugins are live.
A free tier
100 free emails a day, simple public pricing.

Keeps working when your users and agents start sending

Sub-accounts give each user, tenant or agent its own credentials, limits, suppressions, webhooks and suspension path, through the same API you already use. Domain Lockdown and behavior-based policy cover the rest.

Your appOne account, one API

Each sub-account has its own

Credentials
Limits
Suppressions
Webhooks
Suspension path

Customer ASending
Customer BSending
AI agentSuspended
TenantSending

Mailbox providers

An agent misbehaves, so only its sub-account is suspended. Everyone else keeps sending.

Sub-accounts
Each tenant, customer or agent gets its own credentials, limits, suppressions, webhooks and suspension path.
yourapp.com
- Your app’s accountMay send
- Tenant you authorizedMay send
- Any other accountBlocked
Domain Lockdown
Domain owners authorize exactly which accounts may send for them.
Judged by
- Complaints
- Bounces
- Phishing patterns
Never judged by
- Industry
- Format
Behavior-based policy
Senders are judged by complaints, bounces and phishing patterns, not by industry or format.

Deliverability you never have to run yourself

24/7 abuse operations from a company that has delivered email for web hosting providers for twenty years.

24/7: Abuse operations, with real people behind them
20: Years delivering email for web hosting providers

Proven on hosting traffic
Web hosting networks are among the hardest places to send from. Our abuse handling was built there.
Abuse handling is not your job
We watch complaints, bounces and phishing patterns, so you don’t have to build that team.