📚 Supported Input Formats¶

This code generator supports the following input formats:

OpenAPI 3.0/3.1/3.2 (YAML/JSON, OpenAPI Data Types); OpenAPI 2.0 (Swagger) has limited support.
AsyncAPI 2.x/3.x (YAML/JSON).
JSON Schema (JSON Schema Core / JSON Schema Validation).
Apache Avro schema (.avsc, Apache Avro).
XML Schema (XSD).
Protocol Buffers / gRPC (.proto, Protocol Buffers / gRPC).
GraphQL schema (GraphQL Schemas and Types).
MCP tool schemas (--input-file-type mcp-tools, MCP Tool Schemas).
JSON / YAML / CSV data (converted to JSON Schema before model generation).
Python dictionary (converted to JSON Schema before model generation).
Existing Python types via --input-model: Pydantic models, dataclasses, Pydantic dataclasses, TypedDict, and dict schemas.

Use --input-file-type auto (the default) for common files, or set an explicit type when a file extension is ambiguous. For example, YAML can contain either an OpenAPI/JSON Schema document or raw sample data, so use jsonschema, openapi, or yaml depending on the intended input.

📘 OpenAPI 3 and JSON Schema¶

Below are the data types and features recognized by datamodel-code-generator for OpenAPI 3 and JSON Schema.

Schema Feature Support (from code)¶

The JSON Schema and OpenAPI feature matrix below is generated from the same code metadata used by the schema version support page.

JSON Schema Features¶

Feature	Introduced	Status	Description
`Null in type array`	2020-12	✅ Supported	Allows `type: ['string', 'null']` syntax for nullable types
`$defs`	2019-09	✅ Supported	Uses `$defs` instead of `definitions` for schema definitions
`prefixItems`	2020-12	✅ Supported	Tuple validation using `prefixItems` keyword
`Boolean schemas`	Draft 6	✅ Supported	Allows `true` and `false` as valid schemas
`$id`	Draft 6	✅ Supported	Schema identifier field (`id` in Draft 4, `$id` in Draft 6+)
`definitions/$defs`	Draft 4	✅ Supported	Key for reusable schema definitions
`exclusiveMinimum/Maximum as number`	Draft 6	✅ Supported	Numeric `exclusiveMinimum`/`exclusiveMaximum` (boolean in Draft 4)
`readOnly/writeOnly`	Draft 7	✅ Supported	Field visibility hints for read-only and write-only properties
`const`	Draft 6	✅ Supported	Single constant value constraint
`propertyNames`	Draft 6	✅ Supported	Dict key type constraints via pattern, enum, or $ref
`contains`	Draft 6	⚠️ Partial	Count constraints are modeled when contains matches every item; general schema-valued contains is not supported
`deprecated`	2019-09	⚠️ Partial	Marks schema elements as deprecated
`if/then/else`	Draft 7	❌ Not Supported	Conditional schema validation
`contentMediaType/contentEncoding`	Draft 7	⚠️ Partial	Content type and encoding hints for strings
`contentSchema`	2019-09	⚠️ Partial	Schema for decoded string content
`$anchor`	2019-09	✅ Supported	Location-independent schema references
`$vocabulary`	2019-09	❌ Not Supported	Vocabulary declarations for meta-schemas
`unevaluatedProperties`	2019-09	⚠️ Partial	Additional properties not evaluated by subschemas
`unevaluatedItems`	2019-09	⚠️ Partial	Additional items not evaluated by subschemas
`dependentRequired`	2019-09	❌ Not Supported	Conditional property requirements
`dependentSchemas`	2019-09	❌ Not Supported	Conditional schema application based on property presence
`$recursiveRef/$recursiveAnchor`	2019-09	✅ Supported	Recursive reference resolution via anchors
`$dynamicRef/$dynamicAnchor`	2020-12	✅ Supported	Dynamic reference resolution across schemas

OpenAPI-Specific Features¶

Feature	Introduced	Status	Description
`nullable`	OAS 3.0	✅ Supported	Uses `nullable: true` for nullable types (deprecated in 3.1)
`discriminator`	OAS 3.0	✅ Supported	Polymorphism support via `discriminator` keyword
`webhooks`	OAS 3.1	✅ Supported	Top-level webhooks object for incoming events
`$ref with sibling keywords`	OAS 3.1	⚠️ Partial	$ref can coexist with description, summary (no allOf workaround)
`itemSchema`	OAS 3.2	✅ Supported	Media Type Object item schema for sequential media
`$self`	OAS 3.2	✅ Supported	Root document URI for relative and absolute reference resolution
`querystring`	OAS 3.2	✅ Supported	Query string parameter object without a parameter name
`xml`	OAS 3.0	⚠️ Partial	XML serialization metadata (name, namespace, prefix)
`externalDocs`	OAS 3.0	⚠️ Partial	Reference to external documentation
`links`	OAS 3.0	❌ Not Supported	Links between operations
`callbacks`	OAS 3.0	❌ Not Supported	Callback definitions for webhooks
`securitySchemes`	OAS 3.0	❌ Not Supported	API security mechanism definitions

✅ Implemented data types and features¶

Implemented Data Types and Formats¶

The schema type, format, and default Pydantic v2 type columns below are generated from the parser's schema format registry and the default Pydantic v2 type mapping; keyword and note columns document supplemental schema details.

Schema Data Types¶

Schema Type	Default Pydantic v2 Type	Supported Keywords
`integer`	`int`	maximum, exclusiveMaximum, minimum, exclusiveMinimum, multipleOf
`number`	`float`	maximum, exclusiveMaximum, minimum, exclusiveMinimum, multipleOf
`string`	`str`	pattern, minLength, maxLength
`boolean`	`bool`	-
`object`	`Dict[str, Any]`	properties, required, additionalProperties, patternProperties
`null`	`None`	-
`array`	`List[Any]`	items, prefixItems, minItems, maxItems, uniqueItems

Common Formats (JSON Schema + OpenAPI)¶

Schema Type	Format	Default Pydantic v2 Type	Notes
`integer`	`default` (no `format`)	`int`	-
`integer`	`int32`	`int`	-
`integer`	`int64`	`int`	-
`integer`	`date-time`	`AwareDatetime`	-
`integer`	`unix-time`	`int`	-
`integer`	`unixtime`	`int`	-
`number`	`default` (no `format`)	`float`	-
`number`	`float`	`float`	-
`number`	`double`	`float`	-
`number`	`decimal`	`Decimal`	-
`number`	`date-time`	`AwareDatetime`	-
`number`	`time`	`time`	-
`number`	`time-delta`	`timedelta`	-
`number`	`unixtime`	`int`	-
`string`	`default` (no `format`)	`str`	-
`string`	`byte`	`Base64Str`	Base64 encoded string
`string`	`date`	`date`	-
`string`	`date-time`	`AwareDatetime`	-
`string`	`timestamp with time zone`	`AwareDatetime`	-
`string`	`date-time-local`	`NaiveDatetime`	-
`string`	`duration`	`timedelta`	-
`string`	`time`	`time`	-
`string`	`time-local`	`time`	-
`string`	`path`	`Path`	-
`string`	`email`	`EmailStr`	Requires email-validator
`string`	`idn-email`	`EmailStr`	Requires email-validator
`string`	`idn-hostname`	`str`	-
`string`	`iri`	`str`	-
`string`	`iri-reference`	`str`	-
`string`	`uuid`	`UUID`	-
`string`	`uuid1`	`UUID1`	-
`string`	`uuid2`	`UUID`	-
`string`	`uuid3`	`UUID3`	-
`string`	`uuid4`	`UUID4`	-
`string`	`uuid5`	`UUID5`	-
`string`	`uri`	`AnyUrl`	-
`string`	`uri-reference`	`str`	-
`string`	`uri-template`	`str`	-
`string`	`json-pointer`	`str`	-
`string`	`relative-json-pointer`	`str`	-
`string`	`regex`	`str`	-
`string`	`hostname`	`str`	-
`string`	`ipv4`	`IPv4Address`	-
`string`	`ipv4-network`	`IPv4Network`	-
`string`	`ipv6`	`IPv6Address`	-
`string`	`ipv6-network`	`IPv6Network`	-
`string`	`decimal`	`Decimal`	-
`string`	`integer`	`int`	-
`string`	`unixtime`	`int`	-
`string`	`ulid`	`ULID`	Requires python-ulid
`boolean`	`default` (no `format`)	`bool`	-
`object`	`default` (no `format`)	`Dict[str, Any]`	-
`null`	`default` (no `format`)	`None`	-
`array`	`default` (no `format`)	`List[Any]`	-

OpenAPI-Only Formats¶

Schema Type	Format	Default Pydantic v2 Type	Notes
`string`	`binary`	`bytes`	File content
`string`	`password`	`SecretStr`	-

🔗 Other schema¶

enum (as enum.Enum or typing.Literal)
allOf (as Multiple inheritance)
anyOf (as typing.Union)
oneOf (as typing.Union)
$ref (http extra is required when resolving $ref for remote files.)
$id (for JSONSchema)