DCQL (Digital Credential Query Language)

The Digital Credential Query Language (DCQL, pronounced "dak-l") is a JSON-based query language introduced in the OpenID for Verifiable Presentations (OpenID4VP) 1.0 specification. It enables verifiers to express precise requirements for the credentials they need from a holder's wallet.

A DCQL query is a JSON object with two top-level properties:

• credentials (required): An array of Credential Query objects, each describing a specific credential the verifier is interested in.
• credential_sets (optional): An array defining logical groupings and requirements across the requested credentials.

For the full specification, business context, and real-world payment examples, see our concepts article on DCQL in the EUDI Wallet ecosystem.

Building Blocks

DCQL provides a small set of composable building blocks that cover a wide range of verification scenarios:

Building block	Purpose
Credential Query	Requests a specific credential by format, metadata, and claims. The fundamental unit of a DCQL query.
trusted_authorities	Restricts accepted credentials to those issued by specific trust anchors (EU Trust List, EBSI, OpenID Federation).
claims	Specifies which individual claims within a credential are requested, enabling selective disclosure.
claim_sets	Defines acceptable combinations of claims, allowing preferred claims with fallback alternatives.
credential_sets	Groups multiple credential queries with logical rules (AND/OR), supporting mandatory and optional sets.
multiple	When set to true, allows several instances of the same credential type to be returned in a single flow.
values	Constrains accepted claim values to a predefined allowed list.

Developer Workflow Examples

Each example below demonstrates a specific DCQL building block through a complete developer workflow with runnable API calls.

Example	DCQL feature	Scenario
Trusted Authorities	trusted_authorities	Request a University Degree credential only from issuers in the EU Trust List, EBSI, or an OpenID Federation trust anchor.
Claim Sets (Selective Disclosure)	claim_sets	Verify age from a PID credential, preferring a boolean over_21 claim and falling back to the full birthdate.
Credential Sets (Alternatives)	credential_sets	Accept any one of a Passport, PID, or Photo ID for proof of identity.
Combined Credential Sets	Multiple required credential_sets	Require a Photo ID plus a Proof of Address (Utility Bill or Bank Statement).
Mandatory and Optional Sets	Mandatory + optional credential_sets	Require PID and student proof, with optional address proof for an additional discount.
Multiple Credential Instances	multiple: true	Request six recent Bank Statement credentials in a single verification flow.
Values Constraint	values	Accept a PID credential only if the postal code matches an allowed list.