Optic
Open-source API governance tool for detecting breaking changes in OpenAPI specs
Founded
N/A
Starting Price
$0
Category
General
Last updated March 29, 2026
About Optic
<p>Optic is an open-source API governance platform that helps development teams prevent breaking changes, enforce API design standards, and keep OpenAPI documentation accurate. Built on a high-performance Rust engine, Optic diffs API specifications to detect breaking and non-breaking changes, runs configurable linting rules, and integrates directly into CI/CD pipelines and pull request workflows.</p><p>Originally a Y Combinator-backed startup, Optic was acquired by Atlassian in April 2024 and integrated into Compass, Atlassian's developer experience platform. The open-source CLI remains freely available on GitHub and npm, processing everything locally without sending API data to external servers. Optic's "forwards-only governance" approach applies new rules only to new or changed endpoints, making it practical to adopt incrementally without retroactively breaking existing APIs.</p>
Pros & Cons
Pros
- Completely free and open-source CLI with no usage limits
- Detects breaking changes that standard linters miss by diffing spec versions
- Forwards-only governance avoids flooding teams with legacy warnings
- Local Rust-based processing keeps API schemas private and runs fast
- Precision-patches OpenAPI specs from test traffic, reducing manual spec writing
Key Features
OpenAPI Diffing
Compares two versions of an OpenAPI specification to detect all breaking and non-breaking changes, giving developers a clear changelog of what shifted between releases
Breaking Change Detection
Automatically identifies changes that could break API consumers — removed endpoints, changed response schemas, modified required parameters — before they reach production
API Linting & Style Guides
Enforces API design standards and best practices through configurable linting rules and custom style guides that run alongside diff checks
CI/CD & PR Integration
Runs in pull requests to give developers actionable feedback on API changes before merge, with support for GitHub Actions and other CI platforms
Forwards-Only Governance
Applies new linting rules only to new or changed API endpoints, avoiding false positives on legacy APIs and making incremental adoption practical
Traffic-Based Documentation
Captures API traffic from tests, compares it against the OpenAPI spec, and precision-patches the specification with additions, updates, and removals automatically
Pricing
Open Source CLI
$0/month
- OpenAPI diffing and breaking change detection
- API linting and custom style guides
- CI/CD pipeline integration
- Traffic-based spec patching
- Local processing (Rust engine)
Best For
API Versioning & Release Management
Teams shipping public or partner-facing APIs use Optic in CI to catch breaking changes before they reach production, preventing downstream consumer breakage during releases.
API Design Governance
Platform engineering teams enforce consistent API design standards across microservices by running Optic's linting rules in every pull request, ensuring naming conventions and patterns stay uniform.
OpenAPI Documentation Accuracy
Development teams use Optic's traffic capture to automatically keep OpenAPI specs in sync with actual API behavior, eliminating drift between documentation and implementation.
CI/CD API Quality Gates
Engineering organizations add Optic as a quality gate in their CI pipelines to block merges that introduce breaking changes or violate API style guides without manual review.
