{Data validation} ,by /example #

Okyline gives you readable, real-world JSON validation, powered by simple,annotated examples.

Launch Okyline studio

100% Free

Launch Okyline

Your data never leaves your browser

5×shorter than JSON Schema
100% local, no cloud required
Compatible with your existing stack
Easy to read and write
Fast to execute
Exportable to JSON Schema

5×shorter than JSON Schema
100% local, no cloud required
Compatible with your existing stack
Easy to read and write
Fast to execute
Exportable to JSON Schema

Data quality starts with shared understanding

However, most data models are defined too late, buried in code, impossible to align. Okyline brings design-first back into focus, with schemas that are readable, executable, and ready to share from day one.

Designed for humans
Readable syntax, close to your data. Understand it in 5 minutes, master it in one hour.
Interactive schema builder
Design and validate your schema, live, directly on your data.
JSON Schema compatible
Native export to JSON Schema (draft-07). Direct integration with OpenAPI, Ajv, Fastify, Postman...
Ultra fast execution
Tens of thousands of validations per second on a single thread. Perfect for batch processing, ETL, or critical APIs.

Designed for humans

Readable syntax, close to your data. Understandit in 5 minutes, master it in one hour.

Designed for humans

Readable syntax, close to your data. Understandit in 5 minutes, master it in one hour.

Interactive schema builder

Tens of thousands of validations per second on a single thread. Perfect for batch processing,ETL, or critical APIs.

Interactive schema builder

Tens of thousands of validations per second on a single thread. Perfect for batch processing,ETL, or critical APIs.

JSON Schema compatible

Native export to JSON Schema (draft-07). Directintegration with OpenAPI, Ajv, Fastify, Postman...

JSON Schema compatible

Native export to JSON Schema (draft-07). Directintegration with OpenAPI, Ajv, Fastify, Postman...

Ultra fast execution

Native export to JSON Schema (draft-07). Directintegration with OpenAPI, Ajv, Fastify, Postman...

Ultra fast execution

Native export to JSON Schema (draft-07). Directintegration with OpenAPI, Ajv, Fastify, Postman...

{Okyline} is a game changer_

From a simple enriched JSON example, you can declare business constraints in a readable and structured format that can be immediately executed — or exported as a standard JSON schema.

Launch Okyline studio

Launch Okyline

Tired of writing verbose JSON Schema definitions?

What does {Okyline} brings
to your_ data validation #workflow ?

Design-first syntax
What it does
Add validation rules directly inside exampleJSON fields using | suffixes | labels
Real-world impact
Your examples become specs. Instantlyreadable, immediately useful.
Field-levelconstraints
What it does
@, ?, (…), {…}, ~regex~, [min,max], !, $ref, %
Real-world impact
Cover 90% of real-world validations without writing schemas.
Smart type inference
What it does
Automatically detects string, number, boolean, etc.from your example
Real-world impact
No need to declare types manually — less boilerplate
Powerful collections
What it does
Unified syntax for lists and maps with [...] -> constraint
Real-world impact
Write rules for arrays and dictionaries in one consistent format
Reusable components
What it does
$ref, $nomenclature, $regex
Real-world impact
Modular, DRY, and maintainable models
Conditional logic
What it does
$requiredIf, $forbiddenIf, $appliedIf, and their...IfExist variants
Real-world impact
Simple business logical rules baked into the datalayer
Readable UI labels
What it does
Each field can include a human-readable label for docs or forms
Real-world impact
Generate doc pages or forms automatically
JSON Schema compatible
What it does
Okyline models can be transpiled to JSONSchema
Real-world impact
Plug into existing tooling ecosystems
No-code friendly
What it does
Human-first syntax, readable by non-devs
Real-world impact
Perfect for UI builders, documentation, and API design

Design-first syntax

What it does

Add validation rules directly inside exampleJSON fields using |suffixes|labels

Real-world impact

Your examples become specs. Instantlyreadable, immediately useful.

Field-levelconstraints

What it does

@, ?, (…), {…}, ~regex~, [min,max], !, $ref, %

Real-world impact

Cover 95% of real-world validations withoutwriting schemas

Design-first syntax

What it does

Automatically detects string, number, boolean, etc.from your example

Real-world impact

No need to declare types manually — lessboilerplate

Powerfulcollections

What it does

Unified syntax for lists and maps with [...] ->constraint

Real-world impact

Write rules for arrays and dictionaries in oneconsistent format

Reusablecomponents

What it does

$ref, $nomenclature, $regex

Real-world impact

Modular, DRY, and maintainable models

Conditional logic

What it does

$requiredIf, $forbiddenIf, $appliedIf, and their...IfExist variants

Real-world impact

Simple business rules baked into the datalayer

Readable UI labels

What it does

Each field can include a human-readable labelfor docs or forms

Real-world impact

Generate forms or doc pages automatically

JSON Schemacompatible

What it does

okyline models can be transpiled to JSONSchema

Real-world impact

Plug into existing tooling ecosystems

No-code friendly

What it does

Human-first syntax, readable by non-devs

Real-world impact

Perfect for UI builders, documentation, andAPI design

_Uncompromising simplicity#

Okyline syntax combines simplicity and expressiveness. It fits into just a few characters while remaining human-readable and machine-usable.

A simple JSON example is already a valid Okyline schema that defines the structure (field name, object, list, etc.) and the data type (infered from your data examples)

“

field name

suffixes

label

Read the guide

Okyline

JSON Schema

Simple & understandable schema

Okyline

JSON Schema

Simple & understandable schema

Okyline

JSON Schema

Simple & understandable schema

(...)
Value constraints
@
Required
?
Nullable
#
Key
[ , ]
List size
[ : ]
Map keys:size

~…~
Regex
$oneOf
!
Uniqueness
%
Default value
{…}
String lenght
->
Items constraints

Why this syntax ?

You no longer read the constraints, you perceive them.

A symbolic syntax may seem surprising at first, but it is extremely effective.

The symbols act as visual cues : @ , ? , # , { ... } , ( ... ) , [ , ] are quicker to recognize than long, repetitive descriptions. This approach makes reading easier, reduces cognitive effort, and allows for immediate understanding of validation rules.

Typical use cases ?

For whom ?

Okyline suffixes & key words