Compact.js

Compact.js provides a TypeScript-based execution environment for smart contracts compiled with the Compact compiler. When a Compact smart contract is compiled, the output includes a JavaScript file and a TypeScript declaration file.

Compact.js uses these files at runtime to execute the circuits. The circuit execution results are then used by higher-level tools and frameworks (such as Midnight.js) to create and submit transactions to the Midnight blockchain.

For more information, see the Compact language documentation.

Version

Status

Release 3.0.0LATEST

2026-11-05

Artifacts

Summary

Major release for the ledger 9 network upgrade on Mainnet, used by Midnight.js 5.

Runs contracts on Mainnet after the ledger 9 network upgrade, and on Preview.
Built against compact-runtime 0.21.0 and on-chain runtime 4.0.0.
Requires Compact toolchain 0.36.0 for ledger 9 contracts; recompiling changes a deployed contract's verifier keys (breaking).
Adds /v8 and /v9 entry points so you pick the ledger era at import.
Publishes as ESM only (breaking).
Type surfaces are aware of the ledger era; select the era explicitly (breaking).
Preprod moved to ledger 9 on 9 November 2026 and uses 3.0.0 too.