Sessions and sign-in

Endpoints that turn a sign-in into a session, report on that session, end it, and produce a credential for methods that cannot sign in directly.

Method	Path	Credential
POST	/auth/verify	ID token in the body
POST	/auth/session/refresh	Session cookie
POST	/auth/logout	None
POST	/auth/project-access	Session cookie
POST	/auth/exchange	Single-use code in the body
POST	/auth/otp/send	None
POST	/auth/otp/verify	None
POST	/auth/otp/sign-in	None
GET	/auth/bridge/	None
GET	/auth/bridge/:provider/start	None
GET	/auth/bridge/:provider/callback	State cookie set at start

POST /auth/verify

Verifies an ID token, resolves the person behind it, checks approval and the project grant, and sets the session cookie.

Request body.

Field	Type	Required	Detail
idToken	string	Yes	ID token from akn ID sign-in
project	string	Yes	Project the caller is gating on

Approved response, 200. The session cookie is set on this response.

{
  "approved": true,
  "uid": "…",
  "personId": "…",
  "email": "person@example.com",
  "name": "…",
  "role": "user",
  "projects": ["startpage"],
  "groups": []
}

Refused responses.

Condition	Status	Body
Account not approved	200	{"approved":false,"reason":"pending"}
Approved, no grant for project	200	{"approved":false,"reason":"no_project_access"}
A field is missing	400	{"error":"idToken and project required"}
Sign-in proved a phone number only, and that number is on no account	403	{"approved":false,"reason":"phone_not_linked","error":"…"}
Token does not verify	401	{"error":"Invalid token"}

A 200 with approved: false sets no cookie. Test the field, not the status code.

The first successful verification for an unrecognised sign-in creates a person record with status pending. Phone is the exception: it resolves an account that already carries the number and refuses otherwise.

POST /auth/session/refresh

Reports whether the session cookie is still valid, and returns the person behind it. Takes no body.

Response, 200.

{
  "authenticated": true,
  "uid": "…",
  "personId": "…",
  "email": "person@example.com",
  "name": "…",
  "role": "user",
  "projects": ["startpage"],
  "groups": []
}

An X-Remote-User response header carries the email address when one is known.

Condition	Status	Body
No cookie, or the cookie does not verify	401	{"authenticated":false}

The cookie lifetime is unchanged by this call.

POST /auth/logout

Clears the session cookie. Takes no body and no credential. Always answers 200 with {"ok":true}.

The cookie is cleared in the calling browser. Sessions held elsewhere continue until they expire.

POST /auth/project-access

Records that the signed-in person reached a project.

Field	Type	Required
project	string	Yes

Condition	Status	Body
Recorded	200	{"ok":true}
Cookie or project missing	400	{"error":"missing params"}
Cookie does not verify	401	{"error":"Unauthorized"}

POST /auth/exchange

Redeems a single-use code for the person it was issued to. The code is consumed whether or not the person turns out to be approved.

Field	Type	Required
code	string	Yes

Response, 200.

{
  "uid": "…",
  "personId": "…",
  "email": "person@example.com",
  "name": "…",
  "role": "user",
  "projects": ["startpage"]
}

Condition	Status	Body
code missing	400	{"error":"code required"}
Code unknown	401	{"error":"Invalid code"}
Code already redeemed	401	{"error":"Code already used"}
Code past its expiry	401	{"error":"Code expired"}
Code resolves to nothing	401	{"error":"User not found"} or {"error":"Person not found"}
Person not approved	403	{"error":"Account not approved","reason":"pending"}

Email codes

Three endpoints implement sign-in by a six-digit code sent to an email address. The purpose field selects between them.

Purpose	Meaning
signin	Default. An existing person proves control of an address already on their record
request-access	A stranger proves an address is real so an account request can be reviewed

Property	Value
Code format	Six digits
Lifetime	10 minutes
Attempts	Five per code, after which the code is destroyed
Reuse	Single use. Sign-in consumes it
Resend	One code per address per 60 seconds
Volume	Five codes per address per hour

POST /auth/otp/send

Field	Type	Required	Detail
email	string	Yes	Address to send to
purpose	string	No	signin or request-access. Defaults to signin

Condition	Status	Body
Sent	200	{"ok":true}
purpose is signin and no account holds the address	200	{"ok":true}
Address is malformed	400	{"error":"A valid email is required"}
Resent inside 60 seconds	429	{"error":"A code was just sent. Please wait a minute."}
Hourly limit reached	429	{"error":"Too many codes requested. Try again later."}
Mail delivery not configured	503	{"error":"Email is not configured"}
Delivery failed	500	{"error":"Could not send a code"}

A sign-in request for an address with no account is answered identically to a successful send. A caller cannot use this endpoint to test whether an address has an account.

POST /auth/otp/verify

Checks a code without consuming it.

Field	Type	Required
email	string	Yes
otp	string	Yes
purpose	string	No

Condition	Status	Body
Code correct	200	{"valid":true}
Code wrong, or the purpose does not match	400	{"valid":false,"error":"Invalid code"}
Code expired	400	{"valid":false,"error":"That code expired. Request a new one."}
Attempt limit reached	400	{"valid":false,"error":"Too many attempts. Request a new code."}

A wrong code consumes an attempt. An expired code or an exhausted attempt count destroys the code.

POST /auth/otp/sign-in

Consumes the code and returns a custom token for the browser to exchange for an ID token. The purpose is always signin.

Field	Type	Required
email	string	Yes
otp	string	Yes

Condition	Status	Body
Signed in	200	{"customToken":"…"}
Code wrong, expired or exhausted	400	{"error":"…"}
Address holds no account	403	{"error":"No account for that address"}
Account not approved	403	{"error":"Your account is pending"}
Sign-in failed	500	{"error":"Sign-in failed"}

Exchange the custom token for an ID token, then call POST /auth/verify to open a session.

Bridged providers

A bridge carries a sign-in method that cannot be used directly, and finishes by handing a custom token to https://id.akn.me.uk.

Provider	Identifier	State
akn ID, and the providers behind it	zitadel	Available when configured. Select one with the idp parameter
Steam	steam	Available
Instagram	instagram	Not available. Registered and permanently disabled

Accepted idp values on the zitadel bridge are google, linkedin, github, apple and aknid. The browser is sent straight to the provider.

GET /auth/bridge/

Lists the bridges that are usable. Disabled bridges are omitted.

{ "providers": [ { "id": "steam", "label": "Steam", "start": "/auth/bridge/steam/start" } ] }

GET /auth/bridge/:provider/start

Parameter	In	Required	Detail
provider	Path	Yes	Identifier from the table above
redirect	Query	No	Where to send the browser afterwards. Defaults to https://id.akn.me.uk/account
idp	Query	No	Provider to select on the zitadel bridge

Answers 302 to the provider. A state cookie scoped to /auth/bridge is set and is valid for 10 minutes.

redirect must be https on one of the akn hostnames. Any other destination is refused.

GET /auth/bridge/:provider/callback

Called by the provider. Verifies the assertion, resolves or creates the person, and answers 302 to https://id.akn.me.uk/ carrying customToken and redirect query parameters.

Condition	Status	Response
Unknown provider	404	HTML page
Provider disabled	503	HTML page
redirect not allowed	400	HTML page
State missing, altered or older than 10 minutes	400	HTML page
Provider did not confirm the sign-in	401	HTML page
Provider returned no stable account identifier	502	HTML page
Anything else	500	HTML page

Bridge errors are HTML, not JSON. A caller parsing the response as JSON fails on every error path.

A bridged sign-in that matches no existing person creates one with status pending. It never self-approves.

Related

• Authentication covers credential types and the cookie.
• People administration covers approving an account.
• Errors covers the shapes above in full.