Set up Blockfrost

Blockfrost provides RPC access to the Cardano blockchain, allowing you to broadcast transactions and query blockchain data.

To use Blockfrost with our API you'll need to create an API key and submit it to us.

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You'll need to register a blockfrost API key for each network (preprod and mainnet). You only need to perform this action once per network.

1. Step 1: Create an API Key

Sign up at Blockfrost and generate an API key (production or pre-production).

2. Submit Your API Key to Figment

Send your API key to Figment via 👉 POST Blockfrost Project endpoint

(Optional) Retrieve and Remove Your API Key: You can always retrieve your submitted API key via 👉 GET Blockfrost Projects or remove your Blockfrost API key, use the DEL Blockfrost Project endpoint.

Delegating

When you first delegate on Cardano, the first step is to register your stake key and delegate to a stake pool. Figment’s API allows you to do both in a single transaction, making the process simpler and faster.

Step 1: Understand What Happens

When you register a stake key and delegate:

• Your wallet creates a stake key registration certificate on the blockchain.
• This automatically generates a Reward Account (also called a stake address).
• You pay a deposit of 2 ADA for the registration (refundable if you later deregister).
• Your stake is delegated to the chosen stake pool immediately after registration.

Step 2: Generate the Combined Stake Key Registration + Delegation Payload

Figment provides a Cardano API endpoint to generate the transaction payload for both registering a stake key and delegating:

👉 Endpoint: POST /delegate

Key steps:

• Provide your wallet address and the stake pool ID you want to delegate to.
• Figment will return a signing_payload — this includes both the stake key registration and delegation instructions.

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This means you don’t need two separate transactions. Everything is handled in one step.

A stake key is a unique identifier that links your wallet to a reward account. Registering it allows you to earn rewards from staking.

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To enable rewards withdrawal, Cardano requires that stakers either:

• delegate their governance voting power to a delegated representative or
• explicitly abstain from governance voting.

The /delegate endpoint explicitly sets wallet addresses to abstain.

Step 3: Sign & Broadcast

Use your wallet or custody API to sign the signing_payload. After signing, you will receive a signature that can be submitted via:

👉 Endpoint: POST /broadcast

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Signing via Fireblocks API

When signing Cardano transactions via the Fireblocks, the API returns a publicKey and FullSig.
Use these values to create a valid Cardano witness and attach it to the unsigned_transaction_serialized.
The resulting signed transaction can then be broadcast to the Cardano network.

The following JavaScript example demonstrates how to create these witnesses using the pubkey and FullSig values returned by Fireblocks when signing via API.

import { toHex, fromHex, C } from 'lucid-cardano';

const PUBLIC_KEY = "fireblocks-publicKey";
const SIGNATURE = "fireblocks-fullSig";

function createWitness(fullSig, publicKey) {
  const sig = C.Ed25519Signature.from_hex(fullSig);
  const keyBytes = fromHex(publicKey);
  const key = C.PublicKey.from_bytes(keyBytes);
  const vkey = C.Vkey.new(key);
  const witness = C.Vkeywitness.new(vkey, sig);
  const witnessHex = toHex(witness.to_bytes());
  return witnessHex;
}

const witness = createWitness(SIGNATURE, PUBLIC_KEY);
console.log('✅ Witness:', witness);

Transfer

Figment’s API lets you transfer ADA between wallets by generating a transaction payload that you can sign and submit to broadcast.

Step 1: Understand What Happens

• Specify the from_account_address and to_account_address and the amount of ADA.
• Figment builds a transaction payload including inputs, outputs, and fees.
• You sign the payload and submit it to broadcast the transaction on the Cardano network.

Step 2: Generate the Transfer Payload

👉 Endpoint: POST /transfer

Key steps:

• Create a transfer flow by providing network: cardano/preprod
• Provide from_account_address, to_account_address, and amount.
• Figment returns a signing_payload ready to be signed and submitted.

Step 3: Sign & Broadcast

Use your wallet or custody API to sign the signing_payload. After signing, you will receive a signature that can be submitted via:

👉 Endpoint: POST /broadcast