YAMS — Yet Another Modular Syntax

A YAML-based interchange format for modular dataflow graphs: named nodes connected by wires, each wire carrying a time-varying value. The format is domain-general — audio synthesis, control modulation, effect chains, lighting rigs, video mixers, signal-processing pipelines — anywhere named modules exchange values over explicit connections.

YAMS defines structure. It does not define node types, their semantics, or execution. Those come from a catalog: a host supplies one, and the patch names it. That separation is the whole design.

Manifest

Path	What
spec/1.0/yams-spec.md	The format specification — the normative document
spec/	One directory per version; released versions are frozen
conformance/	Test documents every implementation must accept or reject, with a machine-readable manifest

Implementations

yams-swift — the Swift reference implementation. It is a reference, not a privileged one: the specification is the authority, and an implementation in any language that passes the conformance suite is equally valid.

If you write one, the suite is how you know it is right. Open an issue and it can be listed here.

Catalogs

A catalog defines the node types a patch may use, their ports and parameters, and any host-facing presentation metadata. A patch declares which one it needs:

schema: yams/1
catalog: some.catalog/1

The reference implementation validates structure — that a file is well-formed YAMS. It does not know what any node type means; catalog-aware checking belongs to the host.

New implementations should run conformance/ rather than trusting agreement with yams-swift: the suite is what makes the specification testable in any language, and it is the authority on what "valid YAMS" means.

Licensing

The specification and all other prose here are CC BY 4.0. Copyright © 2026 Klaxson Sound LLC.

Attribution: "YAMS — Yet Another Modular Syntax", Klaxson Sound LLC, licensed under CC BY 4.0.

Code samples embedded in the specification are intended to be copied into implementations. To avoid the attribution requirement riding on a few lines of YAML, the example snippets in the specification are dedicated to the public domain (CC0 1.0); the surrounding prose remains CC BY 4.0.

YAMS is not claimed as a trademark: implement it, and name your implementation after it. See TRADEMARKS.md.

Versions

schema: yams/1 in a patch file names the format major version — the only thing a reader needs to decide whether it can load the file at all. The specification document has its own finer-grained version (spec/1.0/), and yams-swift has its own semver again. See spec/README.md for how the three relate.

Contributing

See .github/CONTRIBUTING.md. Contributions are accepted under the licenses above, certified by a Developer Certificate of Origin sign-off (git commit -s).