Velaris, a language that makes promises in the signature

Field notes

Velaris places types, effects, failure behavior, and contract clauses inside function signatures, then describes checking those contracts with the Z3 theorem prover. Its homepage includes a browser playground, a package-install command, standalone builds for Windows, Linux, and macOS, and machine-readable JSON and SARIF diagnostics. A comparison table covers 63 small programs across Velaris, Deno, and Python, including seven correct controls and two explicitly explained misses.