
The most powerful schema description language and data validator for JavaScript.
Free, no paid tierVisit WebsiteThe Bottom Line
- Price
- Free, no paid tier. Compare plans
Key facts
- Defines schemas for JavaScript objects.
- Validates data against defined schemas.
- Ensures data integrity and reduces errors.
Pros
- Enhances data integrity
- Reduces debugging time
- Improves code readability
- Extensive validation rules
- Declarative API
Cons
- Learning curve for new users
- Can add overhead for very simple validation needs
What is Joi?
Available on: Web
Ratings Across the Web
Joi holds an aggregate rating of 4.6 out of 5 from 4 reviews across G2, last checked March 19, 2026.
Ratings aggregated from independent review platforms. Learn more
Key Features
- Schema description language
- Data validation
- Type checking
- Conditional validation
- Error handling
Pricing
Joi is completely free to use with no hidden costs.
Is Joi worth the price?
Joi is a free and open-source library, making its pricing exceptionally fair and generous compared to any paid alternatives.
There are no dollar amounts to consider, as it's entirely free to use. This makes it best for any developer or team looking for a robust schema validation solution without budget constraints.
Reviews

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Joi FAQ
How does Joi help in building robust APIs?
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Source: joi.dev