mailcheap

MailCheap is a newsletter app: write an issue, send it to your list, publish it on the web, from the dashboard or from your AI agent. This repository is the whole app. Self-host it with your own Amazon SES or PostShiba account, or use MailCheap Cloud, which runs this same code.

Features

• AI agents and the dashboard. Everything the dashboard does also works from an AI agent through the MCP server, and from code through the REST API, with the same checks and limits. ChatGPT, Claude and Grok Bot connect with OAuth; Claude Code, Codex and Cursor with an API key. MCP marks sending as an action that can't be undone, so agents ask you first.
• Write, review, send. Write in an editor with slash commands, images and boxes, or send Markdown or a complete HTML email through the API and MCP. Review shows what to fix before sending: subject, preview text, unsubscribe link, Gmail's 100 KB clip, postal address, sender. Then send it, schedule it, or start with your most engaged readers and send to more later.
• Imports from beehiiv, Substack and Mailchimp. Their CSV exports import as they are, with each reader's status and signup date, and so do Kit's, MailerLite's, Buttondown's, Ghost's and EmailOctopus's.
• A website for each newsletter, on a free subdomain on MailCheap Cloud (<slug>.mailcheap.ai), or on your server: every issue gets a page search engines can find, with a signup form, an author page, share images and a sitemap.
• Sending from your own domain, with the DKIM, return path and DMARC records to add and a check for each. On MailCheap Cloud, a newsletter without a domain sends from its own shared address, hello@<slug>.mailcheap.ai.
• Deliverability protections, built in:
  • warm-up: contacts the account never emailed go out as a 5% slice first, and the rest 3 hours later if the slice's bounces and complaints stay low. On MailCheap Cloud, an account's sends also speed up as it proves clean volume;
  • list cleanup, on by default: readers who ignored several issues get one "do you still want this?" email, then stop getting issues;
  • contact cleaning: imports leave out invalid, misspelled (gmial.com), spam trap, role, throwaway and duplicate addresses, domains that can't receive email, and anyone who unsubscribed, bounced or complained before;
  • one never-email list for the whole server: an address the email provider says doesn't exist (for 180 days) or that turned out to be a spam trap (for good) is left out of every account's imports, signups and sends, and only a keyed hash of it is kept;
  • spam and bounce limits: a send pauses past 2% hard bounces or 0.08% complaints, and the account is blocked past 5% or 0.3%, or on a spam trap hit;
  • Gmail's spam rates, which Gmail never reports one complaint at a time: every email carries a Feedback-ID for Gmail's feedback loop (its campaign or newsletter, its account, its kind), and once an admin connects Google Postmaster Tools, MailCheap reads it every day. An account Gmail flags at 0.08% has its sends paused, at 0.3% it's blocked, and the admins hear when the whole domain reaches 0.1%;
  • one-click unsubscribe (RFC 8058) and a signed unsubscribe link in every email, and confirmed opt-in, on by default.
• Several newsletters: up to 3 per account, each with its own contacts, campaigns and website.
• Signups and stats: signup forms and a signup API, welcome emails, open and click tracking that leaves link scanners out, subscribers over time, and reports by inbox provider (Gmail, Outlook, Yahoo, iCloud...).

Write, review, send	The newsletter's website

All names and addresses in the screenshots are made up.

MailCheap Cloud or self-hosted

MailCheap Cloud is this repository with MAILCHEAP_CLOUD=true, which adds open sign-up, plans and Stripe billing. Only active subscribers count toward a plan, not the ones list cleanup marked dormant. Its marketing site (the landing, pricing and legal pages) isn't part of the open source. Every change to the app ships to both.

With your own sending account, you pay your provider for the emails you send: 10,000 readers and 4 issues a month is 40,000 emails, about $4 to $6 on Amazon SES.

Self-hosting

Plan for about an hour, most of it waiting for DNS and for your provider to approve production sending. Self-hosting comes without support: issues are off and setup questions go unanswered.

What you need

Without Redis, MailCheap counts the same rate limits in each server instance's memory. That still stops a script hammering a form, but on serverless hosts the limits aren't shared between instances and reset on each deploy. Add Redis before you put a signup form on a busy site. Without S3 or Blob, image uploads are off; HTML and Markdown campaigns can still use images hosted anywhere.

Environment variables