Trustlines

On Stellar, accounts must explicitly opt in to hold and use assets. This opt‑in is a trustline.

What Are Trustlines?

• A trustline authorizes an account to hold, receive, and transact with a non‑native asset (anything other than XLM) from a specific issuer.

• Without a trustline, an account cannot receive or keep that asset.

• Each trustline requires ~0.5 XLM in base reserve, increasing the minimum balance.

• Trustlines include a limit (maximum balance) and track current balance and liabilities.

Why Trustlines Matter

• Authorization: allow holding a specific asset (e.g., USDC from its issuer).

• Reserves: each trustline consumes XLM reserve to prevent abuse.

• Limits: set the maximum amount the account is willing to hold.

ACTA Adaptation

• Price Per Credential: ACTA charges 1 USDC per issued credential.

• Required Trustlines: participants interacting with credential flows must have a USDC trustline established on the selected network.

• USDC Issuers (from SDK defaults):

  • Mainnet: CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75 (sdk/src/types/types.ts:17-20)

  • Testnet: CBIELTK6YBZJU5UP2WWQEUCYKLPU6AUNZ2BQ4WWFEIE3USCIHMXQDAMA (sdk/src/types/types.ts:21-24)

Practical Impact

• Before issuing or storing a credential, ensure all participating accounts have the USDC trustline set.

• The trustline must be active on the same network used by your dApp configuration (mainNet or testNet).

Next Steps

• Obtain testnet XLM and USDC: see docs/stellar-network/trustlines/testnet-tokens.md.

• Connect a wallet and sign transactions: see docs/developer-guide/wallet-kit-quick-integration.md.