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Universal Resolver

Resolve any DID method. A unified API for decentralized identifier resolution.

Overview​

The Universal Resolver is a server that resolves Decentralized Identifiers (DIDs) across multiple DID methods through a single HTTP interface. Rather than implementing each method yourself, query the Universal Resolver and get back DID Documents.

How It Works​

┌─────────────────────────────────────────────────────────┐
│                 Universal Resolver                       │
├─────────────────────────────────────────────────────────┤
│                                                          │
│  Your App ──► Universal Resolver                        │
│                    │                                     │
│                    ├──► did:web driver                  │
│                    ├──► did:key driver                  │
│                    ├──► did:ethr driver                 │
│                    ├──► did:sov driver                  │
│                    └──► ... 40+ drivers                 │
│                                                          │
│  Single API endpoint:                                   │
│  GET /1.0/identifiers/{did}                            │
│                                                          │
│  Returns: DID Document (JSON)                           │
│                                                          │
└─────────────────────────────────────────────────────────┘

Supported DID Methods​

MethodDescription
did:webWeb domain DIDs
did:keyCryptographic key DIDs
did:ethrEthereum DIDs
did:sovSovrin/Indy DIDs
did:ionBitcoin/Sidetree DIDs
did:pkhPublic key hash DIDs
did:elemElement DIDs
did:v1Veres One DIDs
And 40+ more...

API Usage​

Resolve a DID​

curl https://dev.uniresolver.io/1.0/identifiers/did:web:example.com

Response​

{
  "@context": "https://w3id.org/did-resolution/v1",
  "didDocument": {
    "@context": ["https://www.w3.org/ns/did/v1"],
    "id": "did:web:example.com",
    "verificationMethod": [{
      "id": "did:web:example.com#key-1",
      "type": "Ed25519VerificationKey2020",
      "controller": "did:web:example.com",
      "publicKeyMultibase": "z6Mk..."
    }],
    "authentication": ["did:web:example.com#key-1"]
  },
  "didResolutionMetadata": {
    "contentType": "application/did+ld+json"
  },
  "didDocumentMetadata": {}
}

JavaScript​

const response = await fetch(
  'https://dev.uniresolver.io/1.0/identifiers/did:key:z6MkhaXg...'
);
const result = await response.json();
const didDocument = result.didDocument;

Public Instances​

InstanceURL
DIFdev.uniresolver.io
Sovrinuniresolver.io

Self-Hosting​

Docker​

docker run -p 8080:8080 universalresolver/uni-resolver-web:latest

Docker Compose​

version: '3'
services:
  uni-resolver:
    image: universalresolver/uni-resolver-web:latest
    ports:
      - "8080:8080"

  # Add specific drivers as needed
  driver-did-web:
    image: universalresolver/driver-did-web:latest

  driver-did-key:
    image: universalresolver/driver-did-key:latest

Configuration​

Select which drivers to enable:

# uni-resolver.properties
uniresolver.resolvers=did-web,did-key,did-ethr

uniresolver.resolver.did-web.url=http://driver-did-web:8080/
uniresolver.resolver.did-key.url=http://driver-did-key:8080/

Architecture​

Driver Model​

┌─────────────────────────────────────────────────────────┐
│                 Universal Resolver                       │
│  ┌─────────────────────────────────────────────────────┐│
│  │               Core Resolver                         ││
│  └───────────────────────┬─────────────────────────────┘│
│                          │                               │
│    ┌─────────────────────┼─────────────────────┐        │
│    │                     │                     │        │
│    ▼                     ▼                     ▼        │
│ ┌──────────┐       ┌──────────┐       ┌──────────┐    │
│ │ did:web  │       │ did:key  │       │ did:ethr │    │
│ │  Driver  │       │  Driver  │       │  Driver  │    │
│ └──────────┘       └──────────┘       └──────────┘    │
│                                                          │
└─────────────────────────────────────────────────────────┘

Each driver is:

  • A separate Docker container
  • Responsible for one DID method
  • Implements standard driver API

Creating a Driver​

public class MyDidDriver implements Driver {
    @Override
    public ResolveResult resolve(String identifier) {
        // Parse DID
        // Fetch DID Document
        // Return result
    }
}

Use Cases​

Identity Verification​

Resolve DIDs to get public keys for signature verification.

Credential Verification​

Look up issuer DIDs when verifying credentials.

Service Discovery​

Find service endpoints from DID Documents.

Multi-Method Support​

Support users with different DID methods without implementing each one.

Resolution Process​

1. Receive DID: did:web:example.com
2. Extract method: "web"
3. Route to did:web driver
4. Driver fetches: https://example.com/.well-known/did.json
5. Return DID Document to client

Comparison​

ApproachProsCons
Universal ResolverOne API, many methodsExternal dependency
Direct resolutionNo dependencyImplement each method
did-resolver libsLocal, fastStill need method libs

Standards​

  • W3C DID Resolution spec
  • W3C DID Core spec
  • DIF Universal Resolver spec

See Also​