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Loop SDK

Loop SDK allows dApps to connect to a Loop account.

What is Loop SDK?

Loop SDK is a lightweight JavaScript client that allows dApps to securely connect to the Loop wallet. It handles the connection flow, performs session validation, and provides a Provider object so your application can fetch holdings, query DAML contracts, submit transactions, and sign messages.

The SDK also includes a server-side signing flow for integrators who want to sign and submit transactions without a wallet popup. This server flow requires access to the user's private key.

Supported contracts

Loop SDK can sign and submit any DAML transaction whose packages are installed on the Loop validator. Today that includes:

  • Splice packages, including Canton Coin and the token standard interfaces (transfer and allocation instructions).
  • Digital Asset Utility packages (registry, credential and related apps). See the Utility DAR releases for package names and versions.
  • Third-party packages that have passed Five North's DAR review and been deployed to the Loop validator.

If a command references a template that isn't installed, the transaction is rejected with TEMPLATES_OR_INTERFACES_NOT_FOUND.

Need your own DAML templates on the Loop validator? See Custom contracts.

Security Considerations

Browser dApps should never handle private keys directly. For best security:

  • Do not request or store private keys.
  • Avoid persisting sensitive fields (e.g., authToken, party_id, email) outside memory.
  • Always use HTTPS.
  • Verify user identity on your backend before performing sensitive actions.

Server SDK (No Popup)

The server SDK lets your backend sign and submit transactions programmatically. This removes the wallet popup but requires key custody.

  • Use @fivenorth/loop-sdk/server
  • Initialize with privateKey + partyId
  • Authenticate, then prepare → sign → execute

If you do not control the private key, you must use the normal wallet popup flow instead.

Example ideas: - List pending transfers - Accept a pending transfer

Next steps

  • See Usage Guide for installation and basic examples.
  • See API Reference for full method and type documentation.
  • See Custom contracts if your dApp needs its own DAML templates.
  • See Changelog for release history.