Type Mapping Overview

How Protocol Buffer types map to GraphQL types.

Quick Reference

Protobuf	GraphQL
`message`	`type` (object) + `input`
`message` with `squash_union`	`union`
`message` with `interface`	`interface`
`enum`	`enum`
`oneof`	`union`
`repeated T`	`[T!]!`
`optional T`	`T` (nullable)

Scalar Type Mapping

Protobuf	GraphQL (ts-proto)	GraphQL (protobuf-es)
`int32`, `uint32`, `sint32`, `fixed32`, `sfixed32`	`Int`	`Int`
`int64`, `uint64`, `sint64`, `fixed64`, `sfixed64`	`String`	`Int64`
`float`, `double`	`Float`	`Float`
`string`	`String`	`String`
`bool`	`Boolean`	`Boolean`
`bytes`	`Byte`	`Byte`
`google.protobuf.Timestamp`	`DateTime`	`DateTime`

See Scalars for complete mappings and customization.

Nullability Rules

Field Type	GraphQL Output	GraphQL Input
Regular field	Nullable	Nullable
`// Required.` comment	Non-null (`!`)	Non-null (`!`)
`// Output only.` comment	Included	Excluded
`// Input only.` comment	Excluded	Included
`repeated` field	`[T!]!`	`[T!]!`

See Fields for detailed nullability control.