capnp-json

A Cap'n Proto JSON codec for capnp-rust, wire-compatible with the C++ capnp::JsonCodec.

The published crate lives in crates/capnp-json/ — see its README for usage and supported features, or the rendered API docs at https://docs.rs/capnp-json.

Releasing

capnp-json follows SemVer. While the crate is on 0.x, breaking changes bump the minor version (0.1.0 → 0.2.0) and backward-compatible changes bump the patch version (0.1.0 → 0.1.1).

Releases are cut by the Release workflow. To publish a new version:

1. Make sure main is green on CI and contains everything you want in the release.
2. From the GitHub Actions tab, run Release via Run workflow and enter the new version (e.g. 0.2.0, no v prefix).

The workflow then:

• bumps version in the root Cargo.toml (and the install snippet in the crate README on minor bumps);
• refreshes Cargo.lock and runs cargo test --workspace;
• runs cargo publish --dry-run as a sanity check;
• commits the bump as Release vX.Y.Z, tags vX.Y.Z, and pushes both;
• publishes to crates.io;
• creates a GitHub release with auto-generated notes.

docs.rs picks up the new version from crates.io automatically — give it a few minutes and check https://docs.rs/capnp-json.

Required setup

• CARGO_REGISTRY_TOKEN repository secret — a crates.io API token from https://crates.io/me, scoped to publish-update for capnp-json.
• The default GITHUB_TOKEN is enough for the commit/tag push and release creation, provided main doesn't have branch protection that blocks pushes from github-actions[bot]. If it does, either relax the rule for the bot or swap in a fine-grained PAT.

License

Licensed under the MIT License.

Copyright (c) 2025 Ben Jackson and Cap'n Proto contributors.