Micro SaaS

Turn sample JSON into a strict, valid JSON Schema

JSONSchema turns a sample JSON object into a JSON Schema (draft 2020-12), explains each required field, and screens it with a deterministic compliance ruleset (type/required/format/enum). Export the schema your API can enforce.

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json-schema-rules@2026-07-19
Ruleset
7
Compliance checks
2020-12
Draft
<30s
Time to schema
Why JSONSchema

Schemas your API can actually enforce

Sample JSON to JSON Schema (draft 2020-12)

A deterministic compliance screen catches missing types and bad formats before you ship.

Auto-marks required fields with explanation

A deterministic compliance screen catches missing types and bad formats before you ship.

Deterministic compliance ruleset (json-schema-rules@2026-07-19)

A deterministic compliance screen catches missing types and bad formats before you ship.

Flags missing type / bad format / duplicate enum

A deterministic compliance screen catches missing types and bad formats before you ship.

From sample to schema in 3 steps

1

Paste

Drop in a sample JSON, pick strictness and purpose.

2

Generate

Model writes a draft 2020-12 schema, then the compliance ruleset screens type/required/format/enum.

3

Report

Export the schema + explanation with a runId.

Live studio

Try it on this page

or generate a schema below.

Generate schema

Result

Your output will appear here.

Simple plans that scale

Free
$0
  • 10 workflow runs / mo · watermarked export
  • Studio demo (no extra LLM fee)
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$19/mo
  • 300 workflow runs / mo · audit log · JSON/CSV export
  • Audit log · CSV/JSON export · fair-use cost guard
  • Priority support · Yearly $190
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Enterprise
Custom
  • SSO-ready · BYOK · higher caps · shared rulesets
  • Optional BYOK (your OpenAI key)
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FAQ

Is the schema valid out of the box?

It follows draft 2020-12 and is screened by a deterministic compliance ruleset. For production, validate it against your real data with a library like Ajv.

Does it check type / required / format / enum?

Yes. The ruleset (json-schema-rules@2026-07-19) flags a missing root type, required keys not in properties, unknown formats, and duplicate enum values.

Do I need my own OpenAI key?

No for Free/Pro. AI runs are included via our platform key (fair use). Enterprise can optionally bring your own key (BYOK) at /settings — the key stays server-side only.

What is Fair Use / what if I hit the AI limit?

Pro includes about 300 workflow runs/month (fair use cost guard on gpt-4o-mini, plus a daily cap). If you hit the limit, Studio returns HTTP 429 — upgrade, wait for reset, enable Demo mode, or use Enterprise BYOK. We never silently return fake AI success.

Is checkout secure?

Payments are processed by Waffo Pancake (merchant of record).

Does this guarantee my API is validated?

No. It is decision-support: a model-assisted schema plus a deterministic compliance screen. Wire the exported schema into your API validator to actually enforce it.

Ship a schema you can enforce

Join developers using JSONSchema. Free to try — no card needed.

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