The Arazzo Specification at Version 1.1.0
Building on the strong foundation of Arazzo 1.0, Arazzo Specification version 1.1.0 brings a host of new features.
This minor release delivers on something the community has been eagerly anticipating: AsyncAPI support.
For the first time, Arazzo workflows can declaratively describe sequences of calls that span both synchronous and asynchronous APIs — a workflow can now coordinate HTTP operations alongside event-driven interactions, all in a single machine-readable document. Alongside that headline addition, version 1.1 brings meaningful improvements to workflow composition, data selection, and several areas of specification precision that practitioners raised during the 1.0 lifecycle.
Summary of Changes
Here’s a quick summary of the headline changes in Arazzo 1.1.0:
- AsyncAPI support. The sourceDescriptions object now accepts asyncapi documents alongside openapi and arazzo Async steps define a send or receive action, support correlation identifiers for request/response linking, timeouts, and explicit step dependencies via dependsOn.
- Chained workflow execution. Action Objects now fully support calling other workflows, with explicit input mapping via a parameters This makes it straightforward to compose reusable sub-workflows — such as token refresh flows — into larger sequences.
- Advanced Selector support. A new Selector Object enables precise, fine-grained data extraction from structured data using jsonpath, xpath, or jsonpointer. Selectors are available across workflow outputs, step outputs, request body payloads, and parameter values. The Expression Type Object (renamed from Criterion Expression Type Object) allows pinning a specific expression language version where required.
- OpenAPI 3.2 alignment. The Parameter Object gains a querystring option for the in field, aligning with the equivalent feature in OpenAPI 3.2 and enabling the full URL query string to be treated and mapped as a single value.
- Identity-based referencing. A new $self field at the root of an Arazzo description provides a canonical URI for the document. Implementations referencing an Arazzo description by URI must use $self if present, removing ambiguity in multi-document workflow systems.
- Clarification improvements. A complete ABNF grammar for runtime expressions, explicit source description resolution ordering, and formally defined Truthy/Falsy evaluation semantics for success criteria conditions.
Upgrade Process
Arazzo 1.1.0 is a minor release. Existing Arazzo 1.0.x documents remain valid and no structural changes have been made to the core workflow description model.
If you are adopting any of the new features — particularly AsyncAPI source descriptions or the Selector Object — you will need to update your arazzo version field to 1.1.0. For tool vendors, we recommend reviewing the release notes on GitHub to assess any impact on parsers, validators, or execution engines.
As always, we recommend that tooling makers avoid locking to a specific minor version where possible, as our intent is to maintain backward compatibility across the 1.x line.
A Growing Ecosystem
The Arazzo tooling ecosystem has expanded significantly since the 1.0 release. Editors, validators, parsers, resolvers, generators, and standalone workflow execution engines are all available. To make tool discovery easier, we’ve added a comprehensive listing to the Arazzo repository README. This complements the openapi.tools website, which has also recently added Arazzo-specific tooling listings.
Looking Ahead
With Arazzo 1.1.0 delivered, work is already underway on future versions.
The proposed roadmap includes:
- Support for gRPC, GraphQL, SOAP, MCP, and A2A step types.
- Actor-in-loop support (human or agent) for workflows requiring approval or intervention.
- Transformer and function support.
- Loops.
We anticipate continuing to evolve the specification at a measured but steady pace. As with the 1.x line to date, backward compatibility will be preserved across minor releases.