Looking for an EmailJS alternative?
EmailJS invented this category, and we say so. What we add: the same call signatures, a hardened key model, and a full delivery platform behind the send.
Facts verified 2026-07-17 — corrections: hello@emailfast.dev
EmailJS created frontend email — browser sends with a public key, no backend required — and category creators deserve their credit. @email-fast/browser is a drop-in replacement: the same call signatures, and an EmailJS-compatible endpoint that accepts the same request shape. The structural difference, and the things a full platform adds, are below.
The comparison
| EmailJS | Email Fast | |
|---|---|---|
| Frontend sending | The category creator: browser sends with a public key | Same model, same call signatures — @email-fast/browser is a drop-in replacement |
| Pricing | Not verified by us — check their site | Free tier: 2,500 emails/month, never expires; contacts and subscribers are never billed — we price sending, not the size of your audience. (pricing) |
| Behind the send | — | Email Fast runs its own mail transfer agent, warmup engine, reputation breaker, and per-tenant fair queue — the pipes are ours, not resold |
The structural difference
Any key that ships to a browser is public the moment the page loads — so the design question is what a leaked key can do. Our answer: a browser SDK with EmailJS-compatible endpoints — the recipient always comes from the server-stored template, never from the request, so a public key in your frontend can't be abused to spam arbitrary addresses.
Behind that front door, every browser send goes through the same machinery as our REST API: every send — REST, SMTP, browser SDK, compatibility endpoints, broadcasts, automations — passes through one admission gate: idempotency, suppression, quota, and content policy in a single checkpoint no ingress can skip. Delivery events come back as webhooks signed with timestamped HMAC-SHA256 (Stripe-style t=…,v1=…), with delivery hardened against server-side request forgery.
Where EmailJS is the right choice
- It already works. A reliable contact form is a solved problem; even a small switch has a cost. No unmet need, no reason to move.
- You want the original, single-purpose tool — the one that defined the category — rather than a platform with a larger surface to learn.
Switching
Swap the package, keep your call sites, store the template server-side, and run it against a sandbox key — sandbox keys (ef_sandbox_…) that run the real pipeline dry: real validation, real rendering, real events, a hosted capture inbox — and no email leaves. Live delivery opens at launch. The walkthrough: /migrate/emailjs.
EmailJS is a trademark of its owner; Email Fast is not affiliated with or endorsed by them. Facts about EmailJS were verified on their public pages on the date above — corrections: hello@emailfast.dev.
Questions, answered plainly
Is it really the same API?
The browser SDK keeps EmailJS call signatures and the compatible endpoint accepts the same request shape — the switch is designed as a package swap plus a key. What changes is where the recipient lives: a browser SDK with EmailJS-compatible endpoints — the recipient always comes from the server-stored template, never from the request, so a public key in your frontend can't be abused to spam arbitrary addresses.
What if someone extracts my public key from the page?
That's the scenario the design assumes: a browser SDK with EmailJS-compatible endpoints — the recipient always comes from the server-stored template, never from the request, so a public key in your frontend can't be abused to spam arbitrary addresses. The worst case is sends of your own template to its configured recipient — not a spam relay.
Do I still avoid running a backend?
Yes. Templates are stored on our servers and the browser sends with a public key. If you add a backend later, the platform is ready for it — SDKs for the browser (EmailJS-compatible), Node.js, Python, PHP, Go, and Ruby, plus a zero-dependency CLI and a published OpenAPI specification.
What does a full platform add to a contact form?
A place to test without consequences — sandbox keys (ef_sandbox_…) that run the real pipeline dry: real validation, real rendering, real events, a hosted capture inbox — and no email leaves — plus suppression handling and delivery events: webhooks signed with timestamped HMAC-SHA256 (Stripe-style t=…,v1=…), with delivery hardened against server-side request forgery.