---
id: dcql-overview
title: "DCQL (Digital Credential Query Language)"
hide_title: false
description: Introduction to the Digital Credential Query Language (DCQL) as defined in OpenID4VP 1.0, with a summary of its building blocks and developer workflow examples.
sidebar_label: Overview
keywords: [DCQL, Digital Credential Query Language, OpenID4VP, credential query, verifiable presentations, EUDI Wallet, credential request, selective disclosure]
slug: /dcql-overview/
---

> **Build this with an AI coding agent.** Install the iGrant.io Agent Skills, then ask your agent to build the integration:
>
> ```bash
> npx skills add L3-iGrant/skills
> ```


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](https://openid.net/specs/openid-4-verifiable-presentations-1_0.html) 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](/concepts/eudi-wallet-dcql-openid4vp-business-wallet-payments/).

## 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. You can also try these scenarios live in the [iGrant.io DCQL demos](https://igrant.io/demo.html?filter=tech-dcql) and watch walkthroughs on the [iGrant.io YouTube channel](https://www.youtube.com/@iGrantio).

| Example | DCQL feature | Scenario |
|---|---|---|
| [Trusted Authorities](/docs/dcql-basic-credential-query-with-trusted-authority/) | `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)](/docs/dcql-2-4-2-claim-set-age-verification) | `claim_sets` | Verify age from a PID credential, preferring a boolean `over_21` claim and falling back to the full `birthdate`. |
| [Credential Sets (Alternatives)](/docs/dcql-2-4-3-credential-set-proof-of-identity-alternatives/) | `credential_sets` | Accept any one of a Passport, PID, or Photo ID for proof of identity. |
| [Combined Credential Sets](/docs/dcql-2-4-4-kyc-request-photo-id-address-proof/) | Multiple required `credential_sets` | Require a Photo ID plus a Proof of Address (Utility Bill or Bank Statement). |
| [Mandatory and Optional Sets](/docs/dcql-2-4-5-student-transport-pass/) | Mandatory + optional `credential_sets` | Require PID and student proof, with optional address proof for an additional discount. |
| [Multiple Credential Instances](/docs/dcql-2-4-6-loan-application-multiple-bank-statements/) | `multiple: true` | Request six recent Bank Statement credentials in a single verification flow. |
| [Values Constraint](/docs/dcql-2-4-7-delivery-service-restricted-postal-codes/) | `values` | Accept a PID credential only if the postal code matches an allowed list. |

## Related

- [OpenID4VP credential verification](/concepts/openid4vp-credential-verification/) shows where a DCQL query fits in the full verifier flow.
- [OpenID4VCI credential issuance](/concepts/openid4vci-credential-issuance/) covers how the credentials that DCQL queries are first issued.