Type Builder

Types describe the shapes your API sends and receives. The Type Builder is the leftmost rail in the app; every endpoint's params, bodies, and responses are built out of these.

Primitives

• string — optional minLength, maxLength, pattern (regex), enum (list of allowed literals).
• number — floating-point. Optional min, max, enum.
• integer — whole numbers. Same constraints as number.
• boolean — true or false.
• null — the literal null.
• literal — a single concrete value ("active", 42, true, null). Useful inside unions as a discriminator.

Composites

Array

array wraps any element type. Optional minItems / maxItems. An example on an array pre-fills the Run panel with sample data.

Object

object is a named bag of fields. Each field has a name, a type, a required flag, and an optional description. Set strict to reject responses that carry fields your spec doesn't know about — useful when you want to catch silent backend additions.

Union

union is a list of variants. A value validates if it matches any variant. Pair with literal discriminators for tagged unions:

{
  "kind": "union",
  "variants": [
    { "kind": "object", "fields": [{ "name": "status", "required": true, "type": { "kind": "literal", "value": "ok" } }, { "name": "data", "required": true, "type": { "kind": "ref", "ref": "Todo" } }] },
    { "kind": "object", "fields": [{ "name": "status", "required": true, "type": { "kind": "literal", "value": "error" } }, { "name": "message", "required": true, "type": { "kind": "string" } }] }
  ]
}

Ref

ref points at another type by name. Cycles are allowed — a TreeNode object with a field of type array<ref:TreeNode> is fine; the runtime validator detects cycles at descent time.

Examples

Any composite (or array / string) can carry an example value. When you open the Run panel for an endpoint whose request body references a type with an example, the body textarea pre-fills with the example. This is the fastest way to sanity-check a request shape.

Delete guard

Deleting a type that's still referenced would silently break endpoints. Instead, the delete action opens a dialog listing every reference — endpoints, other types, request bodies, response types. You have two choices:

• Cancel (default). Remove the references first, then delete.
• Force delete. The type is removed; every reference becomes a validation error highlighted in the endpoint editor until you fix it.

Use Force delete only when you're about to replace the type — otherwise Cancel and refactor.

Where types are stored

Types live at the top level of the spec file as a name-keyed object. See Core Concepts for how types relate to endpoints and environments.