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Version CI Version Unstoppable Domains Documentation Get help on Discord


Resolution-Java is a library for interacting with blockchain domain names. It can be used to retrieve payment addresses and IPFS hashes for decentralized websites.

Resolution-Java is primarily built and maintained by Unstoppable Domains.

Resolution supports different decentralized domains. Please, refer to the Top Level Domains List


The most recent release of this library is available on JitPack.

We are no longer supporting Maven Central for new versions of the resolution-java library.



Java 8+ version is required to use this library.

Default Ethereum Providers

resolution-java library provides zero-configuration experience by using built-in production-ready Alchemy endpoint by default. Default Ethereum provider is free to use without restrictions and rate-limits for UNS resolution.

Custom Ethereum provider configuration

You may want to specify a custom provider:

  • if you want to use a dedicated blockchain node
  • if you want to monitor app usage
  • if you already have a provider in your app to re-use it for domain resolution

Default provider can be changed by using the builder class ResolutionBuilder.

// Default config:

DomainResolution resolution = new Resolution();

// Optionally override default config using builder options:
// providerUrl overwrites chainId by making net_version JSON RPC call to the provider
// in the following example blockchain would be set to the rinkeby testnet
// Note: if a custom configuration is provided for one UNS layer,
// it should be provided for the other layer too

String polygonProviderURL = ALCHEMY_POLYGON_API;

DomainResolution resolution = Resolution.builder()
                .unsProviderUrl(UNSLocation.Layer1, ethProviderURL)
                .unsProviderUrl(UNSLocation.Layer2, polygonProviderURL)

// Custom provider config:

DomainResolution resolution = Resolution.builder()
                .provider(new IProvider() {
                    public JsonObject request(String url, JsonObject body) throws IOException {
                        // TODO Make post request to url with given body
                        // and return JsonObject from the response
                        return null;

// Adding a custom header to the DefaultProvider

DefaultProvider myProvider = DefaultProvider
                .setHeader("custom-header", "custom-value")
                .setHeader("new-header", "new-value");

DomainResolution resolution = Resolution.builder()

// All network calls will be made with headers "custom-header" and "new-header" instead of default ones

Live usage examples

Getting a domain's crypto address

Resolving a domain and getting a currency address.

String addr = resolution.getAddress("brad.crypto", "eth");
assertEquals("0x8aaD44321A86b170879d7A244c1e8d360c99DdA8", addr);

// Get address of token present in multiple chains
String usdtErc20Addr = resolution.getMultiChainAddress("brad.crypto", "USDT", "ERC20");
assertEquals("0x8aaD44321A86b170879d7A244c1e8d360c99DdA8", usdtErc20Addr);

String usdtOmniAddr = resolution.getMultiChainAddress("brad.crypto", "USDT", "OMNI");
assertEquals("1Ap8kmF4ZoPjt6ZYAfCaTKsbncky3F8eTV", usdtOmniAddr);

Getting a domain owner's Ethereum address

Each decentralized domain is owned by someone on the blockchain and held within their wallet. The following command will return the domain owner's Ethereum address.

String owner = resolution.getOwner("brad.crypto");
assertEquals("0x8aad44321a86b170879d7a244c1e8d360c99dda8", owner);

You can also get the result in a batch format for UNS:

List<String> domains = Arrays.asList("brad.crypto", "homecakes.crypto");
Map<String, String> owners = mainnetResolution.getBatchOwners(domains);
assertEquals("0x8aad44321a86b170879d7a244c1e8d360c99dda8", owners.get("brad.crypto"));
assertEquals("0xe7474d07fd2fa286e7e0aa23cd107f8379085037", owners.get("homecakes.crypto"));

Getting a domain's IPFS hash

Decentralized websites host their content on decentralized file storage systems such as IPFS. To get the IPFS hash associated with a domain (and therefore its content), you can use the getIpfsHash method.

String ipfs = resolution.getIpfsHash("brad.crypto");
assertEquals("Qme54oEzRkgooJbCDr78vzKAWcv6DDEZqRhhDyDtzgrZP6", ipfs);

Getting a domain's record

Retrieve any record of domain. Applications sometimes set custom records for a domain to use within their application. To read these records, use the getRecord method.

String record = resolution.getRecord("ryan.crypto", "custom.record.value");
assertEquals("Example custom record value", record);


If the domain you requested is not registered or doesn't have the record you are looking for, this library will throw a NamingServiceException error with one of these codes. We recommend creating customized errors in your app based on the return value of the error.

public enum NSExceptionCode {

Please see the Resolution-Java Error Codes page for details of the specific error codes.


Build & test

Note: if you don't wish to install Gradle you can use it with wrapper: ./gradlew instead of gradle.

  • To run a build with associated tests, use gradle build.
  • To run a build without running the tests, use gradle build -x test.

Internal network config

Internal network config can be updated by running the gradle pullNetworkConfig task and committing the updated file.

Versioning & release process

On codebase updates

  • Contributors should update with the listed changes, and increment the client version in client.json.

New packages

  • Create a new Github release (using semver);
  • Wait for a successful Github Workflow publishing;
  • Release staging repository by logging into Nexus Repository Manager and performing 'close' and then 'release' actions.

As an alternative to a CI release, you can perform a manual publish by following these steps:

  • Configure environment variables: nexusUsername, nexusPassword, signingKey, signingPassword;
  • Run gradle publish;
  • Login to Nexus Repository Manager and perform 'close' and then 'release' actions on a staged repository OR run gradle closeAndReleaseRepository.


Contributions to this library are more than welcome. The easiest way to contribute is through GitHub issues and pull requests.

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Get help

Join our discord community and ask questions.

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