Migrate JSON Schema Draft

draft-04 / 06 / 07 → 2020-12 · with a change log · updated 28 July 2026

Upgrade an older JSON Schema to draft 2020-12. definitions becomes $defs with $refs repointed, boolean exclusiveMinimum becomes numeric, tuple items arrays become prefixItems, and dependencies splits into dependentRequired and dependentSchemas. Every change is listed in the status bar.

How to migrate a JSON Schema to draft 2020-12

1. Paste your existing schema. The declared $schema is reported so you can confirm what you started from.
2. Pick the target draft — 2020-12 unless a tool in your stack is pinned to 2019-09.
3. Read the change list in the status bar. Every rewrite is named with the path it happened at.
4. Validate a known-good document against the migrated schema with Schema validator before replacing the original.
5. Copy or download the migrated schema.

Every rewrite it performs

• id → $id (draft-04 spelled it without the dollar).
• definitions → $defs, and any $ref of the form #/definitions/X repointed to #/$defs/X.
• Boolean exclusive bounds → numeric. Draft-04's {"minimum": 5, "exclusiveMinimum": true} becomes {"exclusiveMinimum": 5}.
• Tuple validation → items: [A, B] becomes prefixItems: [A, B], and additionalItems becomes the new items.
• dependencies → split by value type into dependentRequired (arrays) and dependentSchemas (objects).
• divisibleBy → multipleOf, and draft-06's constant → const.
• draft-03 required: true on a property is dropped, with a note — 2020-12 lists required keys on the parent instead.
• $schema set to the target draft's URI, and $schema / $id / title moved to the top for readability.

What you still have to check by hand

Two 2020-12 changes are behavioural rather than syntactic, so no tool can fix them for you:

• $ref siblings now apply. In draft-07 and earlier, keywords next to a $ref were ignored. In 2019-09 and later they are evaluated. If your schema relied on the old behaviour — for example a $ref with a type beside it that used to be dead weight — the meaning changes.
• Unevaluated keywords. unevaluatedProperties and unevaluatedItems are new and interact with allOf composition in ways that additionalProperties did not. Schemas that used additionalProperties: false inside an allOf branch often need rethinking.

Test with real documents. A migrated schema that parses is not necessarily a schema that means the same thing.

Privacy

Nothing is uploaded. The conversion runs in this tab using your own browser's JavaScript engine — no server sees your data, and the page keeps working with the network disconnected.

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