Update a data contract#

Since Dash Platform v0.22, it is possible to update existing data contracts in certain backwards-compatible ways. This includes:

  • Adding new documents

  • Adding new optional properties to existing documents

  • Adding non-unique indices for properties added in the update.

In this tutorial we will update an existing data contract.



The following example demonstrates updating an existing contract to add a new property to an existing document:

const Dash = require('dash');

const clientOpts = {
  network: 'testnet',
  wallet: {
    mnemonic: 'a Dash wallet mnemonic with funds goes here',
    unsafeOptions: {
      skipSynchronizationBeforeHeight: 650000, // only sync from early-2022
const client = new Dash.Client(clientOpts);

const updateContract = async () => {
  const { platform } = client;
  const identity = await platform.identities.get('an identity ID goes here');

  const existingDataContract = await platform.contracts.get('a contract ID goes here');
  const documents = existingDataContract.getDocuments();

  documents.note.properties.author = {
    type: 'string',


  // Make sure contract passes validation checks
  const validationResult = await platform.dpp.dataContract.validate(

  if (validationResult.isValid()) {
    console.log('Validation passed, broadcasting contract..');
    // Sign and submit the data contract
    return platform.contracts.update(existingDataContract, identity);
  console.error(validationResult); // An array of detailed validation errors
  throw validationResult.errors[0];

  .then((d) => console.log('Contract updated:\n', d.toJSON()))
  .catch((e) => console.error('Something went wrong:\n', e))
  .finally(() => client.disconnect());


Please refer to the data contract reference page for more comprehensive details related to contracts and documents.

What’s Happening#

After we initialize the Client, we retrieve an existing contract owned by our identity. We then get the contract’s documents and modify a document (adding an author property to the note document in the example).The setDocuments method takes one argument: the object containing the updated document types.

Once the data contract has been updated, we still need to submit it to DAPI. The platform.contracts.update method takes a data contract and an identity parameter. Internally, it creates a State Transition containing the updated contract, signs the state transition, and submits the signed state transition to DAPI. A response will only be returned if an error is encountered.

📘 Wallet Operations

The JavaScript SDK does not cache wallet information. It re-syncs the entire Core chain for some wallet operations (e.g. client.getWalletAccount()) which can result in wait times of 5+ minutes.

A future release will add caching so that access is much faster after the initial sync. For now, the skipSynchronizationBeforeHeight option can be used to sync the wallet starting at a certain block height.