What it is: Resend is a developer-first email API that handles both transactional and marketing email, so your login codes, receipts, and your newsletter all ship through one integration.

Email is the classic "boring but load-bearing" problem. Every product needs it — verify an address, reset a password, send a receipt, ping a customer — and almost nobody wants to spend a sprint on it. Resend's pitch is that you shouldn't have to. You call an API, mail goes out, and the deliverability machinery sits behind that call instead of on your to-do list. It's the same bet OpenRouter makes for model APIs: infrastructure you'd rather not build should collapse into one clean call.

Who it's for#

Founders and builders who need email to work and want to move on. That includes:

If you write code and think of email as a feature you call, not a dashboard you live in, this is aimed at you.

Getting started#

Grab an API key from the dashboard, verify a sending domain, and send. The lowest-friction path is a raw HTTP call — no SDK required. The API base is https://api.resend.com and sends are a POST to /emails with a Bearer token:

curl -X POST 'https://api.resend.com/emails' \
  -H 'Authorization: Bearer re_your_api_key' \
  -H 'Content-Type: application/json' \
  -d '{
    "from": "onboarding@resend.dev",
    "to": "you@example.com",
    "subject": "hello world",
    "html": "<strong>it works!</strong>"
  }'

Prefer a real SDK? The official libraries mirror that exact shape. In Python it's resend.Emails.send(params) with the same from / to / subject / html fields, and there are first-party SDKs for Node and other languages too. For anything more than a one-off <strong> tag, Resend maintains React Email — an open-source (MIT-licensed) component library for building email templates in React and TypeScript instead of hand-tuning 2010-era table HTML across Gmail and Outlook. That's the non-obvious win here: you author templates the same way you build your app UI, and the same vendor that sends your mail owns the rendering library.

Pricing#

Resend follows the usual developer-tool model: a free tier to build on, then usage-based paid plans that scale with volume. As of mid-2026 the shape is:

The gotcha to plan around: the free tier also caps you at 100 emails per day. A single busy day — a launch, a password-reset spike — can burn that before you're anywhere near the 3,000 monthly figure, which is what pushes most teams onto Pro sooner than the headline number suggests. Pricing changes, so confirm the current tiers at resend.com/pricing before you build a budget around them.

The catch / where it fits#

Two honest limits.

First, Resend is email infrastructure, not a CRM. It sends mail and manages broadcasts and contacts for sending purposes, but it is not where you run your customer relationships, lifecycle automation, or sales pipeline. If you need branching drip campaigns, lead scoring, or a source-of-truth contact database, Resend is the delivery layer you plug that into — not a replacement for it. Keep your own data store.

Second, the API removes the plumbing, not the DNS. Deliverability still depends on you verifying your domain and publishing DKIM and SPF records so inbox providers trust your mail. Resend makes that setup straightforward and handles the hard parts of sending reputation, but no API can skip domain authentication for you. Sending from an unverified domain, or blasting a cold list, will land you in spam regardless of vendor.

Where it fits: you're building a product, email is a feature you need to ship well, and you'd rather integrate a clean API — with a modern templating story — than stand up your own mail server or wrestle a legacy ESP. That's the sweet spot. For pure marketing-automation needs with no engineering in the loop, look at a dedicated marketing platform instead.