What Sign in with Fidmos is

Fidmos is a centralized identity provider (SSO) built on OAuth2 with the OpenID Connect extension. Fidmos products and partner sites act as OAuth2 clients: they bring the user to us, get a code and exchange it for a token.

Two forms of sign-in

• Embedded window — the sign-in form is rendered by our script (sdk.js) right inside the partner’s document, over their page. The user does not leave for another domain.
• Redirect flow — classic OAuth2: the browser goes to /oauth/authorize, the user signs in and comes back with a code.

Both end the same way: the partner gets an authorization code and exchanges it for a token via POST /oauth/token.

API versions

Our own endpoints live under /api/v1/ — the embed (/api/v1/embed/*) and the Server-to-Server API (/api/v1/users). A breaking contract change will ship as a new /api/v2/ prefix, next to the old one. Protocol endpoints carry no version: /oauth/* and /.well-known/* are defined by the OAuth 2.0 and OpenID Connect specifications — their paths are fixed.

Pairwise sub

The user identifier exposed to you is the sub field. It is pairwise (in OIDC terms — pairwise, a PPID-type identifier): each partner gets its own stable identifier for the same person.

Note

At another partner, the same person gets a different sub. So sub cannot be used as a shared cross-partner key — it identifies the user only within your integration.

Federated, not single sign-on

Sign in with Fidmos on one partner site does not create a session on another. On a second site the person is asked again — an email code, a wallet signature or Telegram. This is by design: each partner runs sign-in itself.

Sign-in methods

A person can sign in with an email code, through Telegram or with a wallet signature (EVM). Which method they chose is a window detail; you get a single result: an authorization code and, after the exchange, a sub. The user may have no email at all (wallet or Telegram sign-in) — then the claims will not include email and email_verified.

Practical integration is in the quick start and the API reference.