The Arazzo Specification is a community-driven, open standard within the OpenAPI Initiative (a Linux Foundation Collaborative Project). It defines a programming-language-agnostic way to express sequences of calls and the dependencies between them to achieve a specific outcome.
Arazzo
Arazzo is a community-driven, open specification within the OpenAPI Initiative that describes sequences of API calls and the dependencies between them to accomplish a specific outcome. Where OpenAPI documents individual operations, Arazzo captures the workflow that strings those operations together — the order, the inputs, and the outputs that flow from one call to the next. It is a programming-language-agnostic, machine-readable way to say not just what an API can do, but how you actually use it to get something done.
- Workflows, not just endpoints - Expresses multi-step sequences and the dependencies between calls, the layer above a single operation.
- Steps, inputs, and outputs - Each step names the operation it invokes and passes outputs forward as inputs to later steps.
- OpenAPI Initiative standard - Governed alongside OpenAPI under the Linux Foundation, so it references existing OpenAPI descriptions directly.
- Language-agnostic and machine-readable - A portable document any tool, SDK generator, or agent can read and execute.
In real operations, Arazzo turns a provider’s “integration” or “recipe” documentation into a forkable, testable artifact — I have used it to re-express partner integrations and health-record retrieval as executable workflows rather than prose. It is especially load-bearing in the agentic turn: an agent handed an Arazzo workflow gets a reliable, pre-authored path through an API instead of having to infer the correct call sequence on its own, and those workflows index cleanly into APIs.json alongside the rest of an API’s artifacts.
The specification is moving again. As of September 2026 four pull requests are queued for Arazzo 1.2 — SOAP/WSDL sources, Protocol Buffer RPC, GraphQL operations and actor-in-the-loop interaction steps — with a Function Object proposal for MCP tools and CLIs still being designed and a conformance-testing issue waiting for someone to take it. The tooling below tracks that: what was ten repositories in August is twenty-seven in September, across eight languages, and the commercial vendors listed have each put an Arazzo surface in front of paying customers. The bi-weekly call is every other Wednesday at 09:00 Pacific.
Industry: API Specification
Also in the data model catalog
This standard shows up on both sides of the house — as a standard applied in API operations here, and as a data model defining what information exists. Same standard, two lenses.
See it as a data model →Open source tools that implement this standard
Harvested from this standard's own governing organisation, with the license read from each repository rather than assumed. The role is what the tool does to the specification, from the shared vocabulary — so an agent holding one of these documents can resolve straight from a goal to a tool.
| Tool | Role | License | What it does |
|---|---|---|---|
| Spectral | validates |
Apache-2.0 | The API style-guide linter — validates OpenAPI, AsyncAPI and Arazzo documents against rulesets you write yourself, and emits ma... |
| Redocly CLI | tests |
MIT | The most production-ready way to EXECUTE an Arazzo document today, and the one most teams already have installed. `redocly resp... |
| libopenapi | parses |
MIT | A high-performance Go library for OpenAPI 2.0, 3.0, 3.1 and 3.2 that also reads Overlay and Arazzo documents into a typed model... |
| Specmatic | tests |
MIT | Executes contracts for both testing and mocking, and is the only Arazzo implementation that will span REST and events in a sing... |
| Speakeasy OpenAPI | parses |
MIT | A Go library and CLI for parsing, validating and transforming OpenAPI, Arazzo and Overlay documents — one of the few toolchains... |
| Bump.sh CLI | documents |
MIT | Deploys, diffs and previews OpenAPI, AsyncAPI and Arazzo documentation, and detects breaking changes between two versions of a ... |
| Arazzo Engine | runs |
Apache-2.0 | A Python runner and generator for Arazzo, and the closest thing the specification has to a reference runtime. The runner handle... |
| Jentic Arazzo Tools | parses |
Apache-2.0 | A TypeScript monorepo of five packages for Arazzo — parser, resolver, validator, runner and UI. It resolves the references an A... |
| Arazzo Toolkit | runs |
Apache-2.0 | A JavaScript/TypeScript monorepo that parses, resolves, validates and RUNS Arazzo documents — separate parser, resolver, valida... |
| Itarazzo | tests |
Apache-2.0 | A Java library that executes Arazzo workflows inside an integration-test context — the steps run as automated end-to-end tests ... |
| arazzo-maestro | validates |
Apache-2.0 | A single Go binary that lints and renders Arazzo workflows. Lint validates against the official JSON Schema, applies semantic r... |
| API Flows Studio | documents |
Apache-2.0 | A web application that loads an Arazzo workflow file and displays it — the workflow viewer for people who need to see the seque... |
| Arazzo CLI | tests |
MIT | A command-line runner for Arazzo workflow documents — executes the steps a workflow describes against real APIs. |
| SpecLynx | parses |
Apache-2.0 | An open source API tooling project, Apache-2.0 throughout, for authors and maintainers of OpenAPI, AsyncAPI and Arazzo — a VS C... |
| roas | validates |
Apache-2.0 | Rust crates for OpenAPI, AsyncAPI, Overlay and Arazzo — every version of each — with a validation CLI. Documents are parsed int... |
| apitapviz | documents |
MIT | A small Python command-line tool that renders an Arazzo file as Markdown or a Mermaid diagram — a human-readable view of the wo... |
| Arazzo Runtime Expression | parses |
Apache-2.0 | A parser, validator, extractor and interpolator for Arazzo Runtime Expressions — the `$inputs.x`, `$steps.y.outputs.z`, `$respo... |
| arazzo2openapi | converts |
Apache-2.0 | Converts an Arazzo workflow description into an OpenAPI description, so a multi-step workflow can be exposed as a conventional ... |
| Arazzo IntelliJ Plugin | authors |
Apache-2.0 | A plugin for IntelliJ IDEA and other JetBrains IDEs that detects Arazzo YAML and JSON files, validates them live against the of... |
| OpenAPI Arazzo for .NET | parses |
MIT | A .NET implementation of the Arazzo specification built to sit alongside Microsoft.OpenApi — parse, build, serialise and valida... |
| Arazzo Criterion | evaluates |
Apache-2.0 | A parser, validator and evaluator for the Arazzo Criterion Object — the success-criteria conditions in `simple`, `regex`, `json... |
| Arazzo MCP Generator | generates |
Apache-2.0 | A CLI that turns an Arazzo document and its referenced OpenAPI files into a fully Dockerised Python MCP server — each workflow ... |
| WSO2 Arazzo Tools | authors |
Apache-2.0 | WSO2's collection of developer tools for Arazzo — a VS Code extension with a workflow designer and visualizer, validation, real... |
| pyarazzo | documents |
MIT | A Python CLI that generates human-readable documentation from an Arazzo document — `pyarazzo doc generate` turns a workflow fil... |
| Arazzo Generator | generates |
MIT | An npm CLI that drafts Arazzo workflows from an OpenAPI document — point it at the description and it writes a starting workflo... |
| Arazzo to Flower | converts |
MIT | A Ruby gem from Bump.sh that transforms Arazzo workflow files into Flower, Bump.sh's own workflow format. Listed because it is ... |
| Tapestry | authors |
MIT | A visual, drag-and-drop workflow builder for Arazzo — connect API operations into sequences on a React Flow canvas and export o... |
Commercial services that support this standard
Vendors with a product surface for this standard — a hosted editor, a runner, a renderer, a test generator — verified on the vendor's own site, not inferred from a blog post. Each links to the vendor's profile on APIs.io.
| Vendor | What they offer | Profile |
|---|---|---|
| Redocly | Respect — a CLI that executes Arazzo workflows against live APIs as contract tests, alongside Arazzo linting in Redocly CLI. | apis.io → |
| Jentic | A hosted Arazzo Editor and ArazzoUI renderer, and the Arazzo Engine runner/generator behind its agent platform; also the renderer WSO2 embeds in its portal. | apis.io → |
| Speakeasy | Generates Arazzo-described end-to-end tests for the SDKs it produces, and maintains the Go library that parses, validates and transforms Arazzo. | apis.io → |
| Bump.sh | Renders Arazzo documentation next to the OpenAPI it references, ships Arazzo support in its CLI and MCP server, and publishes Flower, its own workflow format with an Arazzo converter. | apis.io → |
| WSO2 | The first mainstream gateway vendor to support Arazzo — in its agent/developer portal, through the arazzo-tools developer utilities and VS Code extensions, and through arazzo-mcp-generator, which turns an Arazzo description into a working MCP server. | apis.io → |
| Specmatic | Contract testing that takes Arazzo as an input alongside OpenAPI, AsyncAPI, GraphQL, gRPC and WSDL. | apis.io → |
Referenced on the API Evangelist blog
Where this standard shows up across sixteen years of my writing at apievangelist.com — how it fits into API design, governance, and the agentic turn.
Stedi and EDI as Modern API Workflows
2026-07-08
DrChrono and the Clinical Day as Workflows
2026-07-05
Medplum and FHIR as a Developer Backend
2026-07-04
Arazzo Workflows Are Your New Integration
2026-07-01
