FlaresendTransactional email that runs in your Cloudflare account.
Flaresend is an open-source email API you deploy to Cloudflare. Send over REST from any app, or over RPC from your Workers, with logs, retries, templates and webhooks built in. Nothing sits between your code and Cloudflare.
$ npm install @flaresend/clientimport { Flaresend } from '@flaresend/client';
const flaresend = new Flaresend({
apiKey: process.env.FLARESEND_API_KEY!,
baseUrl: 'https://mailer.acme.com',
});
const { id } = await flaresend.emails.send({
from: 'Acme <hello@acme.com>',
to: 'ada@example.com',
subject: 'Welcome to Acme',
template: 'welcome',
data: { name: 'Ada', appName: 'Acme', loginUrl },
});Built entirely on Cloudflare
- Workers
- D1
- R2
- Queues
- Email Service
- Hono
- React Email
Why Flaresend
An email service you own, not one you rent
Hosted email APIs are easy to start with. Flaresend keeps that ease and moves the whole thing into your own infrastructure.
Runs in your account
The mailer is one Worker you deploy. The email log lives in your D1 database and email bodies in your R2 bucket. No other company sees your mail or your users.
An API you already know
Modeled on Resend: POST /v1/emails, idempotency keys, batch and scheduled sends, typed errors and a typed SDK for Node.js, Bun and Workers.
Open source, MIT
Every line is on GitHub. Read it, change it, fork it, run it for as long as you like. No license keys, no seat limits, no paid tier.
How it works
Accepted in milliseconds, sent from a queue
Your request returns as soon as the email is safely stored. Sending, retrying and tracking happen in the background.
- 01
Your app sends
POST /v1/emailswith an API key from anywhere, orMailerRpc.send()from another Worker. - 02
Flaresend accepts it
Checks the sender, suppressions, size and rate limits. Logs it in D1, stores the body in R2, puts it on a queue and answers 202.
- 03
The queue sends it
A consumer hands it to Cloudflare Email Service. Temporary errors are retried up to 8 times with backoff.
- 04
Events come back
Delivered, bounced and complained events update the log, suppress bad addresses and fire your webhooks.
Features
Everything a transactional email service should do
The parts you would otherwise build yourself around a raw send call.
Batch sending
Up to 100 emails in one request, with a result for each.
Scheduling
Send up to 30 days ahead. Cancel or move it before it goes out.
Templates
React Email templates in Git, plus versioned ones you edit in the dashboard.
Webhooks
Signed events for every delivery step, retried with backoff when your endpoint fails.
Idempotency
Retry any request with the same key and the email is sent once.
Suppressions
Hard bounces and complaints are blocked from then on, automatically.
Domains
SPF and DKIM added to your Cloudflare zones for you.
Open and click tracking
Per project, off by default. Your original HTML is kept as sent.
Test keys
fs_test_ keys go through every check and log the email, but never send it.
Broadcasts
Small, opted-in lists with one-click unsubscribe. Off until you turn it on.
Dashboard
Every email, its timeline and its content. Runs on Workers behind Cloudflare Access.
CLI
The flaresend command manages projects, keys and suppressions, and looks up sent emails.
Dashboard
See every email you send
Open any email to see its full timeline, from queued to delivered, and the exact HTML that went out. Manage keys, domains, templates and webhooks in the same place.
Self-host
From an empty account to your first email
Everything runs on Wrangler. Create the database, bucket and queues, onboard your domain, and deploy.
- No servers, containers or databases to look after
- CI workflow included: migrate and deploy on every push to main
- The dashboard can onboard new domains for you
git clone https://github.com/flaresend-dev/flaresend && cd flaresend
pnpm install && pnpm build && cd apps/mailer
npx wrangler d1 create flaresend
npx wrangler r2 bucket create flaresend-payloads
npx wrangler queues create flaresend-send # + 3 more
npx wrangler email sending enable acme.com
npx wrangler secret put ADMIN_API_KEY
npx wrangler d1 migrations apply flaresend --remote
npx wrangler deployOpen source
All of it. Not an open core.
The mailer, the dashboard, the SDK, the templates, the CLI and these docs are in one repository under the MIT license. There is no hosted edition with extra features. What you see on GitHub is the whole product.
- apps/mailerThe Worker: HTTP API, RPC entrypoints, queue consumers, cron
- apps/dashboardNext.js dashboard, deployed to Workers
- apps/docsThe documentation site
- packages/client@flaresend/client on npm: HTTP, RPC, webhook checks
- packages/templatesReact Email templates rendered in the mailer
- packages/cliThe flaresend command for the admin API
FAQ
Questions
What does it cost?+
Flaresend itself is free and MIT licensed. It runs on your Cloudflare account, so you pay Cloudflare for the Workers, D1, R2, Queues and Email Service it uses, at their prices. There is no Flaresend plan or bill.
How is this different from Resend?+
If you have used Resend, the requests and responses will look familiar. The difference is where it runs: Flaresend is code you deploy to your own Cloudflare account. Your email log, your email bodies and your limits stay under your control.
Can I send newsletters or marketing email?+
No. Cloudflare Email Service is for transactional email, and its terms do not allow marketing or bulk campaigns. Broadcasts exist for small, opted-in lists: they are off per project by default and capped at 500 recipients unless you change the limit.
Do my domains have to be on Cloudflare?+
Cloudflare’s docs say Email Service needs the domain’s DNS on Cloudflare. On those zones Flaresend adds the SPF and DKIM records for you.
Can other Workers send without an API key?+
Yes. Add a service binding to the mailer Worker and call it over RPC. Only Workers in the same Cloudflare account can bind to it.
Send your first email from your own account
Deploy the mailer, create a key, and send. The quickstart takes you through it.