ajv
The fastest JSON Schema validator for v5, v6 and v7 proposals.
Pricing
Free tier
Flat rate
Adoption
→StableLicense
Open Source
Data freshness
Verified · Jul 12, 2026Overview
What is ajv?
ajv is a high-performance JSON Schema validation tool that supports the latest schema versions. It's designed to validate JSON data efficiently, making it an essential tool for developers working with structured data.
Key differentiator
“ajv stands out as the fastest JSON Schema validator, offering support for the latest schema versions with extensive customization options.”
Capability profile
Capability Radar
Honest assessment
Strengths & Weaknesses
↑ Strengths
↓ Weaknesses
ajv primarily focuses on the latest schema versions (v5, v6, and v7), which may leave projects using earlier versions unsupported.
Customizing schemas with keywords and macros requires a deep understanding of ajv's configuration options and can be cumbersome for new users.
While generally fast, ajv may introduce performance bottlenecks when validating deeply nested or large JSON structures due to the complexity of schema validation.
Fit analysis
Who is it for?
✓ Best for
JavaScript and TypeScript developers who need fast, efficient JSON validation
Teams working on large-scale projects where performance is critical
Projects requiring support for the latest JSON Schema proposals
✕ Not a fit for
Developers looking for a web-based UI tool for manual data validation
Projects that require real-time schema updates and revalidation without restarting the application
Cost structure
Pricing
Free Tier
Available
Open source — free to use
Starts at
$0
Model
Flat rate
Enterprise
None
Performance benchmarks
How Fast Is It?
Ecosystem
Relationships
Works well with
Next step
Get Started with ajv
Step-by-step setup guide with code examples and common gotchas.