JSON Schema Generator
Runs in browserGenerate JSON Schema from any JSON object instantly.
Generate JSON Schema from sample JSON with options for draft version, required fields, descriptions, and additionalProperties. Useful for API validation and LLM tool-call schemas.
JSON Schema Generator tool
Schema version
Required fields
Additional properties
Add descriptions
1
2
3
4
5
6
7
8
9
10
11
12
13
14
JSON Schema
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
🔒 Runs in your browser · No uploads · Your data never leaves your device
How to use
Paste JSON sample
Load your object manually or upload a .json file.
Set schema options
Choose draft version, required strategy, descriptions, and additionalProperties behavior.
Copy or download
Copy generated schema or download as .json for validators and OpenAPI specs.
Common use cases
- Generating validation schemas from sample data — Paste a real API response to generate a JSON Schema that can validate future responses of the same shape.
- Documenting API contracts — Generate JSON Schema from example payloads to document request and response shapes in API documentation.
- Bootstrapping TypeScript types — Generate a JSON Schema as an intermediate step before converting it to TypeScript interfaces.
Examples
User profile
Nested object with arrays.
Input{...}Output{ "type": "object", ... }
Frequently asked questions
- How are array item schemas inferred?
- The generator inspects the first non-null item as a representative sample.
- Can I use this for production contracts?
- Yes, but treat generated output as a starting point and review constraints manually.
Key concepts
- JSON Schema
- A vocabulary for describing the structure and constraints of JSON data — defines types, required fields, and value formats.
- draft-07
- A widely-supported version of the JSON Schema specification, compatible with most validators and codegen tools.
- additionalProperties
- A JSON Schema keyword that controls whether object properties beyond those listed are permitted.
Related tools
You might find these useful too.