Implement 'Sign in through Steam' using OpenID 2.0 for web login
domain: partner.steamgames.com · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Add one of Steam's official 'Sign in through Steam' buttons to your login page per branding requirements
Redirect the user to Steam's OpenID 2.0 provider endpoint with your realm and return_to URL
After the user authenticates on steamcommunity.com, handle the redirect back to your return_to URL with OpenID response parameters
Verify the OpenID response by re-checking the signature with Steam's provider (openid.mode=check_authentication) to prevent spoofing
Extract the authenticated SteamID from the claimed_id URL and use it as the account identifier or link to an existing user
Known gotchas
Skipping the check_authentication verification step leaves the login flow forgeable -- the claimed SteamID must be validated server-side, not trusted from the redirect alone
Steam requires using one of their provided sign-in buttons/branding, not an arbitrary custom login UI, per their identity provider terms
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