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Version: 5.14.1

Migrate from v4 to v5

This document only covers the features present in v4 which have changed in some significant way in v5.

If you encounter any missing changes, please let us know and we will update this guide.

number utility replaced by num

To avoid confusion with the native number type, the number namespace has been renamed to num.

// v4
const res = number.isHex(d1);

// v5
const res = num.isHex(d1);

number.toFelt() has been removed, if manual handling is necessary cairo.felt() can be used.

bn.js no longer supported

The bn.js library has been removed in favor of using the native JavaScript BigInt data type.

// v4
const qty = new BN('0x4a8bc');

// v5
const qty1 = BigInt('0x4a8bc');
const qty2 = 32786324915918425n;

The BigNumberish type is now defined as:

  • String representing a number: "123", "0xabc2"
  • Number (max 53 bits): 123
  • BigInt (max 255 bits): 12345612345n

Some commonly used BN utility methods are of course no longer present, however, they have simple equivalents:

  • .mul() and .div(): common operators can be used with bigints: + - * /
  • .umod() can be easily replaced with:
// v4
const c = a.umod(b);

// v5
const tmp = a % b; // a and b are bigint
const c = tmp >= 0n ? tmp : tmp + b;
  • .toarray() can be replaced with num.hexToBytes(a)

ec (elliptic curve)

With the bn.js removal the accompanying elliptic curve libraries have also been replaced, consequently many functions have been relocated or modified.

The concept of a key pair, where the private and public key are used as a single entity, has been removed. ec.getKeyPair(), ec.getKeyPairFromPublicKey() and ec.genKeyPair() do not exist anymore, corresponding methods use the private key directly. Check the following examples:

Account creation:

// v4
const privateKey0 = accountTestnet4PrivateKey;
const account0Address: string = accountTestnet4Address;
const starkKeyPair0 = ec.getKeyPair(privateKey0);
const account0 = new Account(provider, account0Address, starkKeyPair0);

// v5
const privateKey0 = accountTestnet4PrivateKey;
const account0Address: string = accountTestnet4Address;
const account0 = new Account(provider, account0Address, privateKey0);

Derive partial public key (starknetPubKey):

// v4
const starknetPubKey = ec.getStarkKey(keyPair);

// v5
const starknetPubKey = ec.starkCurve.getStarkKey(privateKey); // only X part of full pubKey

Derive full public key (fullPubKey):

// v4
const fullPubKey = encode.addHexPrefix(keyPair.getPublic('hex'));

// v5
const fullPubKey = encode.addHexPrefix(
encode.buf2hex(ec.starkCurve.getPublicKey(privateKey, false))
); // full key

ec.sign and ec.verify:

// v4
const signature = ec.sign(keyPair, msgHash);
const isVerified = ec.verify(inferredKeyPair, msgHash, signature);

// v5
const signature = ec.starkCurve.sign(msgHash, privateKey);
const verifStarknet = ec.starkCurve.verify(signature, msgHash, fullPubKeySource);

pedersen hash calculation:

// v4
const hashMsg = hash.pedersen([account, price]);

// v5
const hashMsg = ec.starkCurve.pedersen(account, price);

'declareAndDeploy' renaming

The account.declareDeploy() method has been renamed to declareAndDeploy():

// v4
const response = await account0.declareDeploy({ contract: compiledTest, classHash: testClassHash });

// v5
const response = await account0.declareAndDeploy({
contract: compiledHelloSierra,
casm: compiledHelloCasm,

Note: declare and declareAndDeploy no longer require classHash! The new ec library is now able to calculate it quickly and does so automatically when it is not provided. If a contract has been written in Cairo 1 the casm property is needed.

Calldata and returned values

Deep modifications and improvements have been performed concerning exchange of data with the Cairo contract functions. The complete new rules are listed in this guide.
In short, it is easier to construct a list of parameters while relying on the built-in verification of the conformity to the abi.
Returned values from a Cairo 0 contract are identical, but returned values from a Cairo 1 contract are easier to recover.

stark.compileCalldata() has been replaced by CallData.compile(). Regardless, the new Contract.populate() and myCallData.compile() methods are the recommended way to create calldata.


Constants for Provider initialization have been updated:

// v4
const providerTestnet2 = new Provider({ sequencer: { network: 'goerli-alpha-2' } });

// v5
const providerTestnet2 = new Provider({ sequencer: { network: constants.NetworkName.SN_GOERLI2 } }); // or SN_GOERLI or SN_MAIN

Provider.chainId() has been removed, Provider.getChainId() should be used.

// v4
const chainId = myProvider.chainId();

// v5
const chainId = await myProvider.getChainId();


The approach to create a uint256 variable has changed:

// v4
const amountIn = uint256.bnToUint256(amountToSwap);

// v5
const amountIn: Uint256 = cairo.uint256(50000n);


In your DAPP React code you can connect to ArgentX or Braavos wallets using the get-starknet library.

The current v2.1.0 version is not yet compatible with starknet.js v5.
An update is expected.