Software company · three products

The parts of your product
you'd rather not build.

DevCoat makes three SaaS products. AuthOwl handles authentication, Billow handles billing and subscriptions, and Hitsend sends transactional email. Each one does a single job, ships with a typed SDK and a REST API, and is meant to be boring in the way infrastructure should be.

  • Typed SDKs
  • REST APIs
  • Use one or all three
import { AuthOwlProvider, SignIn } from '@authowl/react'

export default function App() {
  return (
    <AuthOwlProvider publishableKey={process.env.AUTHOWL_PK}>
      <SignIn />
    </AuthOwlProvider>
  )
}

What the three take off your plate

Products

Three services, one job each.

They share the same ideas about API design and documentation, but they are separate products. Take whichever one you need.

Authentication

AuthOwl

Sign-in, sessions, and everything around them.

A hosted authentication service. Every project is its own isolated tenant with its own users, sessions, sign-in methods and signing keys. The isolation is enforced by Postgres row-level security rather than by application code, so a query that forgets its tenant filter returns nothing instead of somebody else’s rows.

  • Passkeys and WebAuthn
  • Magic links and email one-time codes
  • Social sign-in
  • TOTP two-factor with backup codes
  • JWT issuer with key rotation and published JWKS
  • Append-only audit log
  • React, Next.js and Convex SDKs

Billing

Billow

Subscriptions, entitlements and usage.

A billing engine you can self-host. It owns the subscription state machine, entitlements, coupons and usage-based pricing, and treats the payment provider underneath as a charging rail. Postgres is the only infrastructure it needs: the data, the job queue and the outbox all live there.

  • Subscriptions with proration
  • Entitlement checks
  • Usage metering
  • Coupons and catalog as code
  • Invoices and refunds
  • Console with role-based access
  • MIT licensed

Email

Hitsend

Transactional email with the receipts.

A transactional email API built on AWS SES. It handles domain verification, DKIM, suppression lists and delivery events, then shows you exactly what happened to every message: queued, sent, delivered, bounced or complained, with the content, headers and full event timeline attached.

  • REST API and SMTP
  • Domain verification with DKIM
  • Scoped live and test keys
  • Idempotent sends
  • Full delivery event timeline
  • Content and header viewer
  • Typed SDK with automatic retries

How they fit

Use one.
Or use all three.

They are separate products with separate accounts and separate pricing. Nothing in AuthOwl requires Billow, and nothing in Hitsend requires either of them. They are built by the same people, which is mostly why they feel the same to work with.

Each one has its own SDK, its own API keys, and its own docs. You can adopt one and never touch the others.

AuthOwl, Billow and Hitsend each connect independently to your application AuthOwl Billow Hitsend Your app one, two, or three

How we work

A few things we stick to.

  1. 01

    One job per product

    Each service does a single thing. We would rather ship a small surface that works properly than a wide one that mostly works.

  2. 02

    Documented before it ships

    Every endpoint has a reference page and every SDK has an example you can paste. If something is hard to document, that usually means the API is wrong.

  3. 03

    We use them ourselves

    Hitsend signs its users in with AuthOwl and bills them through Billow. We hit the rough edges on our own time first.

  4. 04

    Boring infrastructure

    TypeScript and Postgres, with as few moving parts as we can get away with. Billow needs nothing but a database. Fewer things to run means fewer things to page someone about.

  5. 05

    Your data stays portable

    Everything is reachable over a plain REST API, so exports are a normal request rather than a support ticket. Billow is MIT licensed and self-hostable if you would rather run it yourself.

Get in touch

Tell us what
you're building.

Questions about any of the three, access to a product, or something you wish one of them did. Same inbox either way, and a person reads it.

or just write to contact@devcoat.com

  • Product access
  • Technical questions
  • Integration help
  • Anything else