The Best API Linting Tools in 2026
We researched API linting tools using official vendor websites, including pricing pages, plan tables, and product documentation. Our rankings focus on how well each product enforces API definition standards and catches specification or consistency errors, alongside value for money and verified features. This guide covers API linting tools.
Our top picks
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Top ranked
Spectral#1 of 198.8/10A customizable JSON and YAML linter for teams enforcing OpenAPI and AsyncAPI standards.
Free plan
-
Runner-up
Zally#2 of 197.9/10A focused OpenAPI linter with REST API, CLI, web UI, and configurable rules.
Open source
-
Top-ranked free plan
IBM OpenAPI Validator#5 of 197.8/10A no-cost command-line validator for OpenAPI documents, with support for custom rulesets.
Free plan
Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.
The full ranking 19 tools, best first
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Best forTeams needing customizable OpenAPI and AsyncAPI linting
A customizable JSON and YAML linter for teams enforcing OpenAPI and AsyncAPI standards.
8.8/10★★★★☆Visit Spectral -
Best forTeams linting OpenAPI 2 or 3 with a web UI
A focused OpenAPI linter with REST API, CLI, web UI, and configurable rules.
- OpenAPI linting
- Custom rules
7.9/10★★★★☆Visit Zally -
Best forTeams pairing API linting with SDK and doc generation
API linting and validation alongside SDK, documentation and portal generation.
7.9/10★★★★☆Visit APIMatic -
Best forTeams wanting broad API linting and reporting
A broad, local-first API linting toolkit with reporting and CI support.
7.9/10★★★★☆Visit vacuum -
Best forOpenAPI teams needing custom validation rules
A no-cost command-line validator for OpenAPI documents, with support for custom rulesets.
- OpenAPI linting
- Custom rules
7.8/10★★★★☆Visit IBM -
Best forTeams needing custom rules across API formats
A community-built CLI for linting OpenAPI, AsyncAPI, and Arazzo with custom rules.
- AsyncAPI linting
- CI integration
- OpenAPI linting
7.6/10★★★★☆Visit OpenLint -
Best forTeams combining OpenAPI linting with live traffic analysis
An open-source CLI for applying shared rules across OpenAPI specs and HTTP traffic.
- CI integration
- OpenAPI linting
- Custom rules
7.5/10★★★★☆Visit Thymian -
Best forTeams using AEPs, Spectral and VS Code
A focused Spectral ruleset for teams validating OpenAPI documents against AEPs.
- OpenAPI linting
7.4/10★★★★☆View AEP Linter -
Best forGraphQL teams using ESLint in their editor workflow
A focused, open-source GraphQL linter for teams working in ESLint-enabled editors.
7.3/10★★★★☆Visit GraphQL ESLint -
Best forGraphQL teams wanting lightweight CI linting
A focused GraphQL schema linter for pre-commit checks and CI pipelines.
- CI integration
- GraphQL schema linting
7.2/10★★★★☆Visit GraphQL Linter -
Best forGraphQL teams checking conventions and breaking changes
An open-source GraphQL CLI for checking schema conventions and breaking changes.
- GraphQL schema linting
- Custom rules
7.1/10★★★★☆Try CrowdStrike gql -
Best forGraphQL teams enforcing schema conventions
A focused, open-source CLI for teams that need configurable GraphQL schema rules.
- GraphQL schema linting
- Custom rules
7.0/10★★★★☆View project -
Best forNode.js users wanting straightforward OpenAPI checks
An open-source OpenAPI checker with CLI and Node.js options.
- OpenAPI linting
6.9/10★★★☆☆Visit OpenAPI Linter -
Best forRust projects linting GraphQL SDL schemas
A focused Rust library and CLI for checking GraphQL SDL naming and deprecation rules.
- GraphQL schema linting
6.8/10★★★☆☆Visit Grafbase -
Best forTeams enforcing Google API standards on Protocol Buffers
A configurable command-line linter for checking protobuf APIs against Google standards and AIP rules.
6.7/10★★★☆☆Visit site -
Best forEnterprises managing API lifecycles and governance
A broad API management platform with governance, analytics, and flexible deployment.
6.4/10★★★☆☆Try IBM API Connect -
Best forTeams already using Postman for API testing workflows
A broad API testing platform, but its supplied feature set does not establish API linting.
6.3/10★★★☆☆Visit Postman -
Best forTeams prioritizing OpenAPI documentation and publishing
A documentation and portal platform, not a clear match for teams seeking API linting.
6.2/10★★★☆☆Visit Redocly -
Best forTeams prioritizing SDK generation from OpenAPI
A focused OpenAPI generation platform, not a clear fit for teams seeking API linting.
6.1/10★★★☆☆Visit Speakeasy
No tools match those filters.
Compare at a glance
| # | Tool | Free plan | Paid from | OpenAPI linting | Score |
|---|---|---|---|---|---|
| 1 | Spectral | Yes | Free | 8.8 | |
| 2 | Zally | Yes | Free | Yes | 7.9 |
| 3 | APIMatic | No | $10/mo | 7.9 | |
| 4 | vacuum | Free | 7.9 | ||
| 5 | IBM OpenAPI Validator | Yes | Free | Yes | 7.8 |
| 6 | OpenLint | Yes | Free | Yes | 7.6 |
| 7 | Thymian | Yes | Free | Yes | 7.5 |
| 8 | AEP OpenAPI Linter | Yes | Free | Yes | 7.4 |
| 9 | GraphQL ESLint | Yes | Free | 7.3 | |
| 10 | GraphQL Linter | Yes | Free | No | 7.2 |
| 11 | CrowdStrike gql | Free | No | 7.1 | |
| 12 | graphql-schema-linter | Yes | Free | No | 7.0 |
| 13 | OpenAPI Linter | Yes | Free | Yes | 6.9 |
| 14 | graphql-lint | Yes | Free | No | 6.8 |
| 15 | Google API Linter | Free | 6.7 | ||
| 16 | IBM API Connect | No | $83/mo | 6.4 | |
| 17 | Postman | Yes | $9/mo | 6.3 | |
| 18 | Redocly | No | $10/seat/mo | 6.2 | |
| 19 | Speakeasy | Yes | 6.1 |
Head-to-head All 28 comparisons →
- Spectral vs Zally
- Spectral vs APIMatic
- Spectral vs vacuum
- Spectral vs IBM OpenAPI Validator
- Spectral vs OpenLint
- Spectral vs Thymian
- Spectral vs AEP OpenAPI Linter
- Zally vs APIMatic
- Zally vs vacuum
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How we rank API linting tools
Every tool on this page was researched by iTechGuides Editors from its official website — pricing pages, plan tables and product documentation. We rank on how well each one does this category's core job, what the free or entry plan includes, and where it falls short. Where we have enough verified facts, the score out of 10 is a rubric — job fit, value and how much we could verify — shown with its breakdown on every tool's page; a tool we have not verified enough to score yet shows its rank without a number. Scores are re-checked when a product changes its plans. Read the full editorial policy, or submit a tool we missed.
Reviewed by iTechGuides Editors · Editorial team · Updated Nov 2026
Last updated · How we research and update