Think of it as Babel.js, but for API specifications.

ApiDOM is the semantic core behind SpecLynx. It powers every layer of the stack: the Language Service, VS Code extension, browser editor, and CLI.

It parses OpenAPI, AsyncAPI, JSON Schema, Arazzo, and Overlay specs into a unified semantic tree you can traverse, transform, and serialize back out.

The goal is simple:

Let developers work with API specs programmatically without losing the structure, style, and intent of the original file.

Because that part matters.

You should be able to modify a spec and get back something that still looks like your file, not a machine-generated rewrite.

What you can build on it

SpecLynx ApiDOM is Apache-2.0 licensed, and you can use it to build your own:

• ✅ Linters
• ✅ Transforms
• ✅ Code generators
• ✅ Migration tools
• ✅ Spec-aware automation

What we did to make it ready

• Tree-sitter based parsing: so tooling stays useful even while specs are incomplete
• A semantic data model: not generic objects, but one that understands OpenAPI Operations and Schema Objects
• Lossless roundtrip: comments, indentation, and key ordering are preserved across transformations
• Performance and memory efficiency for large specs

Why open source it

We open-sourced ApiDOM to build trust. Every line of source code is now auditable and viewable, which also makes it usable in regulated environments where that’s not a nice-to-have but a requirement.

Try it

npm install @speclynx/apidom-reference

Parse an API specification and access its data model right away:

import { parse } from '@speclynx/apidom-reference';
import { toValue } from '@speclynx/apidom-core';

const result = await parse('/path/to/openapi.json');

toValue(result.api.info.title);   // document title
toValue(result.api.info.version); // document version

Get started

• GitHub: speclynx/apidom
• Documentation: speclynx.com/apidom

If you’ve ever had to parse, rewrite, or generate API specs: what broke first? Tell us in the discussions 👇