Email for your app, set up with one command

Postboi is an email provider, and postboi is its TypeScript SDK. Run npx postboi init and mail() sends: no DNS, no card, no other provider to sign up for. Receiving, lists, webhooks and forms are already in the box.

3,000 emails a month are free, for good. After that it's £9 for 40,000 or £25 for 100,000, which is less than Resend charges for the same volume (Postboi or Resend?).

Already have a provider? mail() works with Resend, SES, Postmark and 40-odd others too, so switching is a line of config. You don't need any of them to use Postboi. And when you want more than email, the same API sends SMS, WhatsApp, push and chat.

📖 Docs · Pricing · Postboi compared · Dashboard

Quick start

bunx postboi init

Pick Postboi, sign in in the browser, and you're done. The CLI writes one secret:

# .env
POSTBOI_TOKEN=…

import { mail } from "postboi"

await mail({ to: "[email protected]", subject: "Hi", body: "<p>Hello</p>" })

Mail goes out from [email protected] until you verify your own domain. Everything that isn't a secret (defaults, hooks, the captcha key) goes in a committed postboi.config.ts, and from is typed to the addresses your account can send from.

No one at the keyboard? bunx postboi init --agent sets up a project with no prompts and no sign-in. Sends stay sandboxed until someone claims it with one click. More on that.

What you get

• Sending, domains, lists and broadcasts, contacts, suppressions and a message log, all on the one token. The Postboi provider
• FormData to email. Hand mail() a FormData and it becomes a tidy HTML table, with attachments and grouped fields
• Hosted forms for sites with no backend, and spam protection (honeypot plus an invisible captcha)
• A dev inbox at /__postboi, so mail sent in development never reaches a real person
• Webhooks for delivered, opened, clicked and bounced, in one format whichever provider sent it
• Scheduling, tracking and one-click unsubscribe. Scheduling · Tracking
• Email testing. analyze() checks client support, Gmail clipping, alt text and links, offline, in any test suite
• Any HTML for the body, or Maizzle templates
• One error type, PostboiError, whichever provider failed

Bring your own provider

Pick Bring your own provider in postboi init instead. Your code stays the same:

// postboi.config.ts
import { config } from "postboi"

export default config({ provider: "resend", default: { from: "[email protected]" } })

# .env
RESEND_API_KEY=re_xxxxxxxx

See all providers.

SvelteKit

A contact form action is one line:

// +page.server.ts
import { mail } from "postboi/kit"

export const actions = { default: mail }

Or use remote functions with postboi/remote and skip the server file. Postboi also has guides for Next.js, Astro, Nuxt, Remix, Hono, Express and Cloudflare Workers.

Beyond email

Run bunx postboi init --sms (or --whatsapp, --push, --chat) and call the function:

import { sms, whatsapp, push, slack, send } from "postboi"

await sms({ to: "+447788223344", message: "Your code is 4291" })
await whatsapp({ to: "+447788223344", template: "order_shipped", variables: { name: "Ada" } })
await push({ to: subscription, title: "Order shipped", message: "On its way" })
await slack({ message: "Deploy finished" })

// or try the cheapest channel first and stop when one works
await send({
	to: { push: subscription, sms: "+447788223344" },
	channels: "cheapest",
	message: "Your code is 4291",
})

In development, texts and WhatsApp messages are logged, not sent. SMS · WhatsApp · Push · Chat · send()

For AI agents

• bunx postboi skill installs a skill that teaches the whole library, at .claude/skills/postboi/ and .agents/skills/postboi/. It also ships in the package at node_modules/postboi/skills/postboi/SKILL.md.
• The docs pages render client-side, so fetch plain Markdown from https://docs.postboi.app/raw/<slug>, or everything at once from /llms-full.txt.

Development

bun install
bun run dev     # the docs site
bun run check   # types
bun run lint
bun run test
bun run build   # the package

PRs are welcome, new providers especially. Match the code style (snake_case, no semicolons), add tests, and run check and lint before pushing. Releases are covered in RELEASING.md.