Stabletrust for Private Agentic Finance

Private payments for AI agents. One key. Zero traces.

Stabletrust enables AI agents to transact privately on EVM chains - shield tokens, transfer confidentially, withdraw silently. Balances are encrypted on-chain. No one can see what your agent holds or where it sends.

Built for the private agent economy.

---

Quickstart

No SDK. No setup. Just POST.

// Shield tokens into a confidential account
await fetch("https://stabletrust-api.fairblock.network/deposit", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    privateKey: process.env.AGENT_KEY,
    tokenAddress: "0x036CbD53842c5426634e7929541eC2318f3dCF7e", // USDC
    amount: "10000000", // 10 USDC
    chainId: 84532, // Base Sepolia
  }),
});

That's it. Your agent now has a private balance no one can read.

---

Agent Flow

EOA → [account/create] → Confidential Account → [deposit]  → shielded balance
                                              → [transfer] → Recipient
Recipient → [apply] → spendable → [withdraw] → EOA

1. Create account - provision a confidential account (idempotent). Required before an account can receive a transfer.
2. Deposit - shield ERC-20 tokens. Balance becomes encrypted on-chain.
3. Transfer - send privately to any address. Amount is invisible on-chain.
4. Apply - a recipient applies received funds, moving them from pending to available so they can be spent or withdrawn.
5. Withdraw - unshield back to public ERC-20 at any time.
6. Balance - check any account's decrypted balance. Read-only - sends no transaction.

---

API

POST /account/create

Provision your confidential account (idempotent). Required before an account can receive a transfer.

const res = await fetch("https://stabletrust-api.fairblock.network/account/create", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    privateKey: process.env.AGENT_KEY,
    chainId: 84532,
  }),
});

const { address, created } = await res.json();
// { success: true, address: '0x...', created: true }  // created:false if it already existed

POST /deposit

const res = await fetch("https://stabletrust-api.fairblock.network/deposit", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    privateKey: process.env.AGENT_KEY,
    tokenAddress: "0x036CbD53842c5426634e7929541eC2318f3dCF7e",
    amount: "10000000",
    chainId: 84532,
  }),
});

const { receipt } = await res.json();
// { hash: '0x...' }

POST /balance

Read-only - decrypts and returns the balance without sending any transaction. Returns exists: false with zero balances if the account hasn't been created yet.

const res = await fetch("https://stabletrust-api.fairblock.network/balance", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    privateKey: process.env.AGENT_KEY,
    tokenAddress: "0x036CbD53842c5426634e7929541eC2318f3dCF7e",
    chainId: 84532,
  }),
});

const { exists, balance } = await res.json();
// { exists: true, balance: { total: '10000000', available: '10000000', pending: '0' } }

POST /transfer

const res = await fetch("https://stabletrust-api.fairblock.network/transfer", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    privateKey: process.env.AGENT_KEY,
    recipientAddress: "0x...recipient",
    tokenAddress: "0x036CbD53842c5426634e7929541eC2318f3dCF7e",
    amount: "5000000", // 5 USDC
    chainId: 84532,
  }),
});

const { receipt } = await res.json();
// { hash: '0x...' }

POST /apply

Apply received funds - moves a recipient's balance from pending to available so it can be spent or withdrawn.

const res = await fetch("https://stabletrust-api.fairblock.network/apply", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    privateKey: process.env.AGENT_KEY,
    chainId: 84532,
  }),
});

const { tx } = await res.json();
// { success: true, message: 'Pending balance applied', tx: '0x...' }

POST /withdraw

const res = await fetch("https://stabletrust-api.fairblock.network/withdraw", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    privateKey: process.env.AGENT_KEY,
    tokenAddress: "0x036CbD53842c5426634e7929541eC2318f3dCF7e",
    amount: "5000000",
    chainId: 84532,
  }),
});

const { receipt } = await res.json();
// { hash: '0x...' }

---

Parameters

/deposit

Field	Type	Required	Description
privateKey	string	yes	Agent wallet private key
tokenAddress	string	yes	ERC-20 token contract address
amount	string	yes	Amount in token base units
chainId	number	yes	Target network chain ID
waitForFinalization	boolean	no	Wait for tx finality (default: true)

/balance

Field	Type	Required	Description
privateKey	string	yes	Agent wallet private key (used for decryption)
tokenAddress	string	yes	ERC-20 token contract address
chainId	number	yes	Target network chain ID
address	string	no	Address to query - defaults to wallet from privateKey

/transfer

Field	Type	Required	Description
privateKey	string	yes	Agent wallet private key
recipientAddress	string	yes	Recipient Ethereum address
tokenAddress	string	yes	ERC-20 token contract address
amount	string	yes	Amount in token base units
chainId	number	yes	Target network chain ID
useOffchainVerify	boolean	no	Off-chain proof verification (default: false)
waitForFinalization	boolean	no	Wait for tx finality (default: true)

/withdraw

Field	Type	Required	Description
privateKey	string	yes	Agent wallet private key
tokenAddress	string	yes	ERC-20 token contract address
amount	string	yes	Amount in token base units
chainId	number	yes	Target network chain ID
useOffchainVerify	boolean	no	Off-chain proof verification (default: false)
waitForFinalization	boolean	no	Wait for tx finality (default: true)

/account/create

Field	Type	Required	Description
privateKey	string	yes	Agent wallet private key
chainId	number	yes	Target network chain ID
waitForFinalization	boolean	no	Wait for account finality (default: true)

/apply

Field	Type	Required	Description
privateKey	string	yes	Agent wallet private key
chainId	number	yes	Target network chain ID
waitForFinalization	boolean	no	Wait for tx finality (default: true)

---

Supported Chains

Chain	ID
Base	8453
Base Sepolia	84532
Ethereum Sepolia	11155111
Arbitrum Sepolia	421614
Arc	5042002
Stable	2201
Tempo	42431

stablepay-api