authjs-steam-provider

Auth.js v5 provider for Steam OpenID. Minimal, edge-friendly, and typed. It plugs directly into NextAuth/Auth.js and exchanges the Steam OpenID assertion for a session, then enriches the profile via Steam Web API.

• Provider ID: steam • Peer deps: next (>=13 <16), next-auth (>=5.0.0-beta.18 <6)

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Installation

npm install authjs-steam-provider
# or
yarn add authjs-steam-provider

You also need a Steam Web API Key. Get it at: https://steamcommunity.com/dev/apikey

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Requirements and Configuration

Set the following environment variables:

• NEXTAUTH_URL: Your public app URL (e.g. https://example.com)
• STEAM_API_KEY: Your Steam Web API key

Provider options (required):

• clientSecret: The Steam Web API key
• callbackUrl: Absolute callback base URL for your NextAuth callback route, e.g. ${NEXTAUTH_URL}/api/auth/callback

Notes:

• The provider constructs openid.return_to as ${callbackUrl}/steam and validates the OpenID assertion against it.
• Works on the Edge runtime (no Node-specific APIs).

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Usage (Next.js App Router, Auth.js v5)

File: app/api/auth/[...nextauth]/route.ts

import NextAuth from "next-auth"
import SteamProvider from "authjs-steam-provider"

export const { handlers, auth } = NextAuth({
  providers: [
    // Important: pass the Request to the provider
    (req) =>
      SteamProvider(req, {
        clientSecret: process.env.STEAM_API_KEY!,
        callbackUrl: `${process.env.NEXTAUTH_URL}/api/auth/callback`,
      }),
  ],
})

export const GET = handlers.GET
export const POST = handlers.POST

Client-side sign-in:

import { signIn } from "next-auth/react"

// triggers the Steam OpenID flow
await signIn("steam")

Accessing the session:

import { auth } from "@/app/api/auth/[...nextauth]/route"

export default async function Page() {
  const session = await auth()
  // session.user has id, name, email (synthetic), image
  return <pre>{JSON.stringify(session, null, 2)}</pre>
}

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API Reference

Default export

SteamProvider(req: Request, options: SteamProviderOptions): OAuthConfig<SteamProfile>

• req: The Next.js Request of the current auth route handler.
• options:
  • clientSecret: string — Steam Web API key.
  • callbackUrl: string | URL — Base callback URL (e.g. ${NEXTAUTH_URL}/api/auth/callback).
  • You may also pass standard OAuthUserConfig<SteamProfile> fields via options (as it extends Partial of it), if needed.

Profile mapping

profile(profile: SteamProfile) returns:

{
  id: profile.steamid,
  image: profile.avatarfull,
  email: `${profile.steamid}@steamcommunity.com`, // synthetic (Auth.js requires an email)
  name: profile.personaname,
}

Authorization flow

• Initiates OpenID via https://steamcommunity.com/openid/login.
• Validates assertion server-side with openid.mode=check_authentication.
• Extracts steamId from the claimed identifier.
• Fetches player summary using ISteamUser/GetPlayerSummaries with clientSecret and steamId.

Types

SteamProviderOptions (from src/types/steam.ts):

interface SteamProviderOptions {
  callbackUrl: string | URL
  clientSecret: string
}

SteamProfile is compatible with Steam Web API player summary, including at least:

interface SteamProfile {
  steamid: string
  personaname: string
  avatar: string
  avatarmedium: string
  avatarfull: string
  profileurl: string
  // …additional fields from Steam
}

Provider constants:

• PROVIDER_ID = "steam"
• PROVIDER_NAME = "Steam"
• AUTHORIZATION_URL = "https://steamcommunity.com/openid/login"

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Best Practices and Tips

• Ensure NEXTAUTH_URL matches your deployed domain (including protocol).
• callbackUrl must be absolute and point to your NextAuth callback base: ${NEXTAUTH_URL}/api/auth/callback.
• Use a dedicated environment variable for STEAM_API_KEY; never commit it.
• If you customize session callbacks, keep the user.id sourced from profile.steamid to maintain stable identity.
• The email is synthetic to satisfy Auth.js serialization; don’t use it for outbound email.
• Prefer running the auth route on Edge for lower latency; this provider is edge-safe.
• Handle errors gracefully in UI; Steam may return non-OK responses if the user is private or API is down.

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License

This project is licensed under the MIT License - see the LICENSE file for details.

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Links

• Auth.js Docs (v5): https://authjs.dev
• Issues / Contributing: https://github.com/goncalojbsousa/authjs-steam-provider/issues