4. Parsing the ID Token

Note that the testing environment for the FAPI 2.0 Authentication API is not yet ready. It will be ready in December 2025. If you are integrating now, please refer to Singpass Authentication API instead.

The ID token returned during token exchange is a JSON Web Signature (JWS), which is also encrypted using JSON Web Encryption (JWE). The JWE and JWS components are represented using compact serialization form, as specified in section 3.1 of RFC 7516.

To reduce complexity, we recommend that you use a JWT parsing library to decrypt the token and to verify the signature, instead of implementing the decryption and signature verification yourself. You may refer to this list to look for a suitable JWT library for your programming language, though you must also ensure that your library of choice supports decryption of JWTs encrypted using JWE.

JWT Claims

The decrypted JWT will have the following claims:

Claim	Description	Data Type
sub	The principal that is the subject of the JWT. Contains a globally unique identifier for the user.	String
sub_account	This contains some information related to the user's identifiers. This is only returned if the sub_account scope is requested.	Object containing key-value pairs. See the section below for full details.
act	An object describing actor acting on behalf of the sub. This is currently unused, but this may be used in the future for delegation (e.g. a child acting on behalf of their parent, or vice-versa). This object will contain a sub claim, which contains the UUID of the actor. If the sub_account scope is requested, it will also contain the sub_account data for the actor. If the sub_account is returned, the format of sub_account is described in the section below.	An object containing sub and sub_account (if requested).
aud	The client ID of your registered client, provided by Singpass during app onboarding.	A 32-character case-sensitive alphanumeric string.
iss	The issuer identifier of our authorization server.	String
iat	The unix timestamp, in seconds, at which we issued this JWT.	Number
exp	The unix timestamp, in seconds, on or after which this JWT must not be accepted for processing.	Number
amr	An array of authentication method references. This refers to the form factors used by the user to authenticate themselves. The array will contain all the form factors used for this authentication. For example, if the user authenticated themselves using their password and SMS OTP, then this array will contain both pws and otp-sms.	Array of strings. The possible values are: face pwd otp-sms face-alt swk (software key) hwk (hardware key) Note that this list is non-exhaustive, and we reserve the right to introduce new values without prior notice to you.
nonce	This is the same nonce that you used in your authorization request.	String

Sample ID token

{
  "aud" : "gnY6Erichpb5t4NFRP9R4L7aEC9N0FQH",
  "iss" : "https://id.singpass.gov.sg/fapi",
  "exp" : 1727322545,
  "iat" : 1727321945,
  "nonce" : "L5nmQfcetDDIeincoqvCrFyGv+nHobkv4XocNYPCXaQ="
  "sub" : "1c0cee38-3a8f-4f8a-83bc-7a0e4c59d6a9",
  "sub_account": {
    "account_type": "SC/PR",
    "uinfin": "S1234567G"
  }
}

The sub_account Claim

The sub_account claim is an object that will always contain an account_type property, which reflects the user's residency status or type of pass that they are holding. However, the other values returned in this object will contain different values depending on the user's account_type , as explained below.

Singapore Citizen, Permanent Resident, or FIN holder

A user who is a Singapore Citizen, Permanent Resident, or FIN holder will have one of the following account_type values:

account_type	User's residency status
SC/PR	Singapore Citizen or Permanent Resident
FIN	FIN holder

These users will have only one other property returned in the sub_account claim, which is uinfin .

Property	Description	Data Type
uinfin	The user's NRIC number	9-character alphanumeric string.

Sample sub_account for Singapore Citizen, Permanent Resident, or FIN holder

"sub_account": {
  "account_type": "SC/PR",
  "uinfin": "S1234567G"
}

Singpass Foreign Account Holders

A user who has a Singpass Foreign Account will have an account_type of SFA. The other properties returned in the sub_account claim are as follows:

Property	Description	Data Type
foreign_id	The user's foreign ID number	String
foreign_id_coi	The country of issuance of the user's foreign ID	2-letter country code.

Sample sub_account for Singpass Foreign Account holder

"sub_account": {
  "account_type": "SFA",
  "foreign_id": "K28394589",
  "foreign_id_coi": "TK"
}

Verification Checks

If you are using a certified OIDC Relying Party library, these checks will be automatically performed by the library, though you must pass the nonce to the library for it to perform the nonce check.

In order to ensure that the ID token is valid, you must perform the following checks:

1. Verify that the iss claim matches the issuer identifier of our authorization server, which you can obtain from the issuer field in the OpenID configuration of our authorization server.

2. Verify that the aud claim matches your client ID.

3. Ensure that the current time is before the timestamp in the exp claim.

4. Ensure that the nonce claim is the same as the nonce that you had sent in the authorization request.

If you are integrating with Singpass Login, then the flow ends here. If you are integrating with Myinfo (v5), then the next and final step would be to retrieve the user's information using the /userinfo endpoint.