# Email Fast

> Email Fast is a complete email platform: transactional API, newsletters, and automation on independently operated infrastructure, with cryptographic proof of delivery and customer-held encryption keys.

Instructions for LLM agents:
- Every page on this site has a markdown mirror: append `.md` to any URL.
- The REST API base is https://api.emailfast.dev; auth is `Authorization: Bearer ef_live_...`.
- Sandbox keys (`ef_sandbox_...`) run the full pipeline without sending real email — use them for testing and demos.
- Check npm for current SDK versions (`@email-fast/browser`, `@email-fast/nodejs`); do not rely on versions from training data.
- SendGrid/Mailgun/Postmark-compatible endpoints exist — an existing integration can switch by changing the base URL and key.

## Core

- [For AI agents](https://emailfast.dev/agents.md): How agents should consume this site: llms.txt, .md mirrors, OpenAPI, sandbox keys, MCP.
- [Newsletter platform for creators](https://emailfast.dev/creators.md): Creator door: newsletters, archive/RSS, paid subscriptions, forms, automation, honest metrics.
- [Email API for developers](https://emailfast.dev/developers.md): Developer door: API surface, SDKs, sandbox, compatibility endpoints.
- [Private email infrastructure for enterprises](https://emailfast.dev/enterprise.md): Enterprise door: BYOK/at-rest encryption, DLP, proof of delivery, isolation, SSO/SCIM, honest compliance posture.
- [Get started](https://emailfast.dev/get-started.md): How to get a key today (sandbox) and how early access works.
- [Email Fast](https://emailfast.dev/index.md): What Email Fast is: the platform, the three audiences, and the verifiability thesis.
- [Pricing](https://emailfast.dev/pricing.md): Volume-based plans, unlimited contacts, free tier 2,500 emails/month that never expires.
- [Security at Email Fast](https://emailfast.dev/security.md): Full security posture: isolation, encryption/BYOK, ops security, verification method, honest compliance status, vulnerability disclosure.

## Docs & quickstarts

- [Documentation](https://emailfast.dev/docs.md): Documentation hub — index of quickstarts and reference pages.
- [Send email from the browser](https://emailfast.dev/docs/quickstart-browser.md): Browser quickstart: @email-fast/browser, public keys, origin allowlist, typed template params.
- [Send email with curl (REST API)](https://emailfast.dev/docs/quickstart-curl.md): Raw REST quickstart: send, timeline, suppressions, batch.
- [Send email with Go](https://emailfast.dev/docs/quickstart-go.md): Go quickstart: net/http + encoding/json REST calls, send, timeline, idempotency.
- [Send email with Next.js](https://emailfast.dev/docs/quickstart-nextjs.md): Next.js quickstart: route handler + server action patterns.
- [Send email with Node.js](https://emailfast.dev/docs/quickstart-node.md): Node.js quickstart: install, send, webhooks, idempotency.
- [Send email with PHP](https://emailfast.dev/docs/quickstart-php.md): PHP quickstart: dependency-free stream-context REST calls, send, timeline, idempotency.
- [Send email with Python](https://emailfast.dev/docs/quickstart-python.md): Python quickstart: requests against the REST API, send, timeline, idempotency.
- [Send email with Ruby](https://emailfast.dev/docs/quickstart-ruby.md): Ruby quickstart: Net::HTTP REST calls, send, timeline, idempotency.
- [SMTP relay setup](https://emailfast.dev/docs/quickstart-smtp.md): SMTP relay quickstart: host, ports, auth, TLS rules, idempotent retries.
- [Send email with Django](https://emailfast.dev/send-email-with/django.md): Django recipe: emailer service module + transaction.on_commit, settings-based key.
- [Send email with Express](https://emailfast.dev/send-email-with/express.md): Express recipe: POST route with @email-fast/nodejs, async error propagation, idempotency.
- [Send email with Fastify](https://emailfast.dev/send-email-with/fastify.md): Fastify recipe: schema-validated route with @email-fast/nodejs and async error handling.
- [Send email with Go](https://emailfast.dev/send-email-with/go.md): Go recipe: stdlib net/http POST to /v1/emails with context deadline and status checks.
- [Send email with Laravel](https://emailfast.dev/send-email-with/laravel.md): Laravel recipe: injectable EmailFast service via Http facade, config() key, queue notes.
- [Send email with Next.js: server action or route handler](https://emailfast.dev/send-email-with/nextjs.md): Next.js recipe: server action wired to a form, with the route-handler rule of thumb.
- [Send email with Node](https://emailfast.dev/send-email-with/node.md): Plain Node recipe: minimal script with @email-fast/nodejs, ESM, env key, exit codes.
- [Send email with PHP](https://emailfast.dev/send-email-with/php.md): PHP recipe: ext-curl POST to /v1/emails with status checks, no Composer dependency.
- [Send email with Python](https://emailfast.dev/send-email-with/python.md): Python recipe: stdlib urllib POST to /v1/emails with timeout and HTTPError handling.
- [Send email with Rails](https://emailfast.dev/send-email-with/rails.md): Rails recipe: EmailFast service object + ActiveJob as the mailer replacement.
- [Send email with React](https://emailfast.dev/send-email-with/react.md): React recipe: browser SDK contact form with ef_pub_ key, plus a backend-route variant.
- [Send email with Ruby](https://emailfast.dev/send-email-with/ruby.md): Ruby recipe: stdlib Net::HTTP POST to /v1/emails with use_ssl and status checks.
- [Send email with Svelte](https://emailfast.dev/send-email-with/svelte.md): Svelte recipe: browser SDK contact form, plus a SvelteKit form-action variant.
- [Send email with Vue](https://emailfast.dev/send-email-with/vue.md): Vue recipe: browser SDK contact form with ef_pub_ key, plus a Nuxt server-route variant.

## Features

- [White-label email for agencies](https://emailfast.dev/features/agencies.md): Agency/OEM: branded child workspaces, roll-up console, per-child caps, instant kill-switch; rebilling arms with billing at launch.
- [Email automation journeys](https://emailfast.dev/features/automation.md): Journey engine: durable/versioned/crash-safe, visual canvas, real-time CDP event entry, peeking-safe A/B, send-time optimization.
- [GDPR compliance for email](https://emailfast.dev/features/compliance.md): Compliance mechanics: crypto-shred erasure, retention windows, consent/DPA/subprocessor tracking, EU residency tagging, audit hash chains, legal hold.
- [Email deliverability platform](https://emailfast.dev/features/deliverability.md): Own-MTA deliverability: health-gated warmup, circuit breaker, blocklist shift-off, VERP bounce classes, FBL suppression, DMARC/TLS-RPT ingestion, fair queueing.
- [Email DLP gateway](https://emailfast.dev/features/dlp.md): Outbound DLP: PAN/SSN/secret detectors, block/redact/force-TLS-or-hold, maker-checker release, evaluated at admission and re-checked at send, fail-closed.
- [Transactional email API](https://emailfast.dev/features/email-api.md): REST send surface: durable 202, idempotency, batch 500, send_at scheduling, streams, cancel, suppressions, validation.
- [BYOK email encryption](https://emailfast.dev/features/encryption.md): BYOK/HYOK: enroll/rotate/suspend/revoke, fail-closed instant revocation, subject-DEK at-rest message encryption, crypto-shred, vendor-access transparency log.
- [Double opt-in signup forms](https://emailfast.dev/features/forms.md): Hosted/embeddable forms at /f/:slug, double opt-in via /c/:token, consent records, preference center at /p/:token, captcha fails closed until armed.
- [Send email from the frontend](https://emailfast.dev/features/frontend.md): Browser SDK with EmailJS-compatible endpoints: recipient pinned server-side, origin allowlists, rate caps, typed variable schemas.
- [SSO, SCIM, and account security](https://emailfast.dev/features/identity.md): Identity: SAML SSO + SCIM (enterprise plans), WebAuthn passkeys, TOTP + recovery codes, __Host- cookies and CSRF protection for all accounts.
- [Inbound email parsing](https://emailfast.dev/features/inbound.md): Inbound: routes by address, full parse with SPF/DKIM/DMARC verdicts on email.inbound, reply-intelligence classification, automatic postmaster mailboxes.
- [SendGrid, Mailgun, and Postmark compatible API](https://emailfast.dev/features/migration.md): Drop-in compat: SendGrid /v3/mail/send, Mailgun /v3/:domain/messages, Postmark /email — same admission gate, atomic batches.
- [Newsletter platform with RSS](https://emailfast.dev/features/newsletters.md): Publications: issues, hosted subscribe page, public archive at /n/:pub, RSS, signed view-in-browser links; paid subs and RSS-to-email arm at launch.
- [Message Explorer and Delivery Inspector](https://emailfast.dev/features/observability.md): Message Explorer + Delivery Inspector: per-message timeline, remote-MX transcript (depth arms at launch), signed /s/:token share links, deterministic copilot.
- [Proof of email delivery](https://emailfast.dev/features/proof-of-delivery.md): Ed25519 delivery certificates: keyed-hash recipient, MX, TLS, verbatim SMTP response, WORM hash chain, legal hold, bulk export.
- [Email testing sandbox](https://emailfast.dev/features/sandbox.md): ef_sandbox_ keys run the full pipeline dry with a hosted capture inbox; sandbox rows never touch reputation ledgers.
- [SMTP relay](https://emailfast.dev/features/smtp.md): SMTP relay: 587 STARTTLS / 465 TLS, API key as password, per-recipient admission, AUTH refused before TLS. Arms at launch.
- [Email templates: MJML + Handlebars](https://emailfast.dev/features/templates.md): MJML + Handlebars templates: author-time compilation, versioning, typed variable schemas, injection-rejecting lint, Gmail 102KB clip warning.
- [Email webhooks](https://emailfast.dev/features/webhooks.md): Signed webhooks: evt envelope, t=/v1= HMAC headers, 5-minute replay tolerance, 15 retries with backoff, SSRF-guarded delivery.

## Comparisons & migration

- [beehiiv alternative](https://emailfast.dev/compare/beehiiv-alternative.md): beehiiv vs Email Fast: resold delivery and per-subscriber pricing vs owned pipes, an API on every tier, and no ad systems.
- [Buttondown alternative](https://emailfast.dev/compare/buttondown-alternative.md): Buttondown vs Email Fast: rented delivery and per-subscriber add-on pricing vs owned pipes with those features bundled.
- [EmailJS alternative](https://emailfast.dev/compare/emailjs-alternative.md): EmailJS vs Email Fast: drop-in browser SDK with the same call signatures, server-pinned recipients, and a full platform behind the send.
- [Compare email platforms](https://emailfast.dev/compare.md): Hub for all comparison and migration pages.
- [Kit (ConvertKit) alternative](https://emailfast.dev/compare/kit-alternative.md): Kit (ConvertKit) vs Email Fast: no transactional product and per-subscriber pricing vs one platform with evidence over asserted numbers.
- [Loops alternative](https://emailfast.dev/compare/loops-alternative.md): Loops vs Email Fast: per-contact pricing vs unlimited contacts, infrastructure transparency, and security-page openness.
- [Mailchimp alternative](https://emailfast.dev/compare/mailchimp-alternative.md): Mailchimp vs Email Fast: contact-based tiers and a transactional add-on vs volume pricing with transactional included.
- [Mailgun alternative](https://emailfast.dev/compare/mailgun-alternative.md): Mailgun vs Email Fast: platform-held vs customer-held keys, tier gating, and a drop-in Mailgun-compatible endpoint.
- [Paubox alternative](https://emailfast.dev/compare/paubox-alternative.md): Paubox vs Email Fast: healthcare compliance with provider-held keys vs general-purpose sending with customer-held keys.
- [Postmark alternative](https://emailfast.dev/compare/postmark-alternative.md): Postmark vs Email Fast: track record vs per-message proof, EU servers, content retention, and a drop-in compatible endpoint.
- [Resend alternative](https://emailfast.dev/compare/resend-alternative.md): Resend vs Email Fast: key custody, US-only storage vs EU infrastructure, AI subprocessors, and migration honesty.
- [SendGrid alternative](https://emailfast.dev/compare/sendgrid-alternative.md): SendGrid vs Email Fast: the Twilio brand migration, the expired free tier, and a drop-in compatible endpoint for the SendGrid SDK.
- [Substack alternative](https://emailfast.dev/compare/substack-alternative.md): Substack vs Email Fast: the 10% revenue share and rented delivery vs volume pricing, owned pipes, and no discovery network.
- [Migrate from EmailJS](https://emailfast.dev/migrate/emailjs.md): EmailJS migration: swap @emailjs/browser for @email-fast/browser, same signatures, server-enforced recipient.
- [Migrate from Mailgun](https://emailfast.dev/migrate/mailgun.md): Mailgun migration: keep your client against our compatible /v3/:domain/messages endpoint, or adopt @email-fast/nodejs.
- [Migrate from Postmark](https://emailfast.dev/migrate/postmark.md): Postmark migration: keep /email and /email/batch against our compatible endpoints, or adopt @email-fast/nodejs.
- [Migrate from SendGrid](https://emailfast.dev/migrate/sendgrid.md): SendGrid migration: keep @sendgrid/mail against our compatible endpoint, or adopt @email-fast/nodejs.

## Guides & reference

- [Blog](https://emailfast.dev/blog.md): Blog index.
- [One door in](https://emailfast.dev/blog/one-admission-path.md): Engineering essay on single-gate admission architecture and the missing-suppression-check bug class it eliminates.
- [We made overclaiming a build error](https://emailfast.dev/blog/overclaiming-build-error.md): How this site's copy is mechanically checked against a claims ledger, a banned-phrase lint, and a launch-state gate at build time.
- [What an email receipt should look like](https://emailfast.dev/blog/proof-of-delivery-receipts.md): The case for cryptographic proof of email delivery, and a field-by-field walk through a verifiable delivery certificate.
- [Reading your DMARC reports](https://emailfast.dev/blog/reading-dmarc-reports.md): Practical guide to DMARC rua aggregate reports: enabling with p=none, reading the XML, alignment, and the path to p=reject.
- [Who actually sends your newsletter?](https://emailfast.dev/blog/who-sends-your-newsletter.md): Why most newsletter platforms resell delivery, and how to check any platform's real sender from public sources.
- [What is BIMI?](https://emailfast.dev/glossary/bimi.md): BIMI puts your verified logo next to your messages in supporting inboxes. It requires DMARC at enforcement and, for most providers, a paid VMC certificate.
- [What is an email bounce?](https://emailfast.dev/glossary/bounce.md): Hard bounce, soft bounce, and policy block are three different failures. Confusing them destroys deliverable addresses; here is how to tell them apart.
- [What is a dedicated IP?](https://emailfast.dev/glossary/dedicated-ip.md): A dedicated IP gives your mail its own reputation instead of a shared pool's. When the volume math justifies one, and the real drawbacks nobody mentions.
- [What is DKIM?](https://emailfast.dev/glossary/dkim.md): DKIM signs each email's headers and body with a domain's private key so receivers can verify who sent it and that nothing changed in transit.
- [What is DMARC?](https://emailfast.dev/glossary/dmarc.md): DMARC is the DNS policy that tells receivers what to do when SPF and DKIM fail alignment: none, quarantine, or reject, plus aggregate reports back to you.
- [What is double opt-in?](https://emailfast.dev/glossary/double-opt-in.md): Double opt-in asks new subscribers to confirm by clicking a link before they get mail. Why that click is legal evidence of consent, not just friction.
- [What is email authentication?](https://emailfast.dev/glossary/email-authentication.md): How SPF, DKIM, and DMARC work together to prove an email's origin, and why Gmail and Yahoo made all three mandatory for bulk senders in 2024.
- [What is an ESP?](https://emailfast.dev/glossary/esp.md): What an email service provider actually is, which parts of delivery it runs, and how to tell a real ESP from a platform reselling someone else's pipes.
- [What is a feedback loop (FBL)?](https://emailfast.dev/glossary/fbl.md): A feedback loop (FBL) sends spam complaints back to the sender. How ARF reports work, and why Gmail's aggregate-only loop needs a Feedback-ID header.
- [Email glossary](https://emailfast.dev/glossary.md): Glossary hub — plain definitions of email standards and deliverability terms.
- [What is IP warmup?](https://emailfast.dev/glossary/ip-warmup.md): IP warmup is the gradual volume ramp that earns a new sending address its reputation with each mailbox provider, and what happens to senders who skip it.
- [What is List-Unsubscribe?](https://emailfast.dev/glossary/list-unsubscribe.md): The List-Unsubscribe header explained: RFC 2369 links, RFC 8058 one-click POST, and why Gmail and Yahoo now require it for bulk senders in 2024.
- [What is MTA-STS?](https://emailfast.dev/glossary/mta-sts.md): MTA-STS lets a domain publish an HTTPS policy that forces sending servers to use verified TLS when delivering mail to it, closing the STARTTLS downgrade hole.
- [What is seed testing?](https://emailfast.dev/glossary/seed-testing.md): Seed testing sends your email to a controlled panel of inboxes to estimate folder placement. What it can tell you, and the limits of testing on seeds.
- [What are SMTP ports 25, 465, and 587?](https://emailfast.dev/glossary/smtp-ports.md): What SMTP ports 25, 465, and 587 are each for: server-to-server relay, implicit-TLS submission, and STARTTLS submission, and why ISPs block port 25.
- [What is a spam complaint?](https://emailfast.dev/glossary/spam-complaint.md): What actually happens when someone clicks report spam: how complaints reach senders, Gmail's 0.3% danger line, and why one complaint means instant suppression.
- [What is SPF?](https://emailfast.dev/glossary/spf.md): SPF is a DNS record listing which servers may send mail for your domain. Learn how include chains, the 10-lookup limit, and softfail vs fail work.
- [What is a suppression list?](https://emailfast.dev/glossary/suppression-list.md): A suppression list is the do-not-send ledger built from bounces, complaints, and unsubscribes. It protects your reputation and keeps sending lawful.
- [What is TLS-RPT?](https://emailfast.dev/glossary/tls-rpt.md): TLS-RPT is the reporting companion to MTA-STS: a DNS record that asks sending servers to report TLS failures they hit when delivering mail to your domain.
- [What is transactional email?](https://emailfast.dev/glossary/transactional-email.md): Transactional email is the mail a user's action triggers: receipts, resets, alerts. Why it must be separated from marketing, technically and legally.
- [What is VERP?](https://emailfast.dev/glossary/verp.md): VERP encodes a message's identity into its bounce address, so every returned email identifies exactly which send failed without parsing the bounce text.

## Optional

- [About](https://emailfast.dev/about.md): Email Fast is an independent email platform built on one conviction: an email company should be able to prove what it claims. Who we are and how we built it.
- [Feature-complete, reviewed to zero](https://emailfast.dev/changelog/2026-07-launch-readiness.md): The Email Fast platform completed its full roadmap and a 19-stage adversarial security review, converging to zero confirmed findings. Early access opens.
- [Changelog](https://emailfast.dev/changelog.md): What shipped in Email Fast, dated and plainly described — feature launches and arming milestones. Freshness you can subscribe to, RSS included.
- [Contact](https://emailfast.dev/contact.md): How to reach Email Fast: early access, sales, support, press, and security reports — every address reaches the people who built the platform.
- [Accessibility](https://emailfast.dev/legal/accessibility.md): Email Fast's accessibility statement: our WCAG 2.2 AA target, how we test with automated and manual passes, known limitations, and how to report a barrier.
- [Acceptable use policy](https://emailfast.dev/legal/aup.md): What may not be sent through Email Fast: spam, deception, malware, and abuse — and how enforcement works, including the platform's automatic protections.
- [Data processing agreement](https://emailfast.dev/legal/dpa.md): Email Fast's DPA: processor obligations, the subprocessor list, security measures, breach notification, and audit support — GDPR Article 28 in plain structure.
- [Privacy policy](https://emailfast.dev/legal/privacy.md): Email Fast's privacy policy in plain language: what we collect and why, where it lives, how long we keep it, and your rights — with erasure that destroys data.
- [Subprocessors](https://emailfast.dev/legal/subprocessors.md): The full list of third parties that process data for Email Fast. It's short by design: the platform runs on dedicated infrastructure we operate ourselves.
- [Terms of service](https://emailfast.dev/legal/terms.md): Email Fast's terms of service: what you're agreeing to, what we promise, what's not allowed, and how either side can walk away — written to be read.
- [Press & brand](https://emailfast.dev/press.md): Email Fast press resources: company boilerplate, brand assets and wordmark usage, fast facts you can quote, and a media contact that actually answers.
- [Status](https://emailfast.dev/status.md): Email Fast service status. During early access this page reports platform state directly; at launch it becomes a live status board with published history.