> ## Documentation Index
> Fetch the complete documentation index at: https://fastql.vachagan.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# SDL and introspection

> Inspect the compiled schema as SDL or standard introspection data.

Use `print_schema` for deterministic schema definition language output:

```python theme={null}
from fastql import print_schema

print(print_schema(schema))
```

The development server publishes the same output at `/schema.graphql`. Its
`/schema.json` route executes the built-in introspection query and returns a
GraphQL response object.

Introspection includes schema roots, named types, fields, arguments, input fields,
interfaces, enum values, possible types, directives, deprecations, and nested type
references.

```bash theme={null}
curl http://127.0.0.1:7691/schema.graphql
curl http://127.0.0.1:7691/schema.json
```

SDL and introspection are derived from the compiled `Schema`; they are not separate
sources of truth.