GraphQL · Function

printSchema

printSchema converts a GraphQL schema object into SDL text. The text can be published to a schema registry for governance automation.

How it works

printSchema converts a GraphQL schema object into SDL text. The resulting string can be submitted to a registry or used by tooling that consumes a schema definition.

Syntax

printSchema(schema)

Parameters

Name	Type	Description
`schema`	`GraphQLSchema`	The GraphQL schema object to serialize as SDL.

Returns

A string containing the schema in GraphQL SDL form.

Key points

Import printSchema from the graphql package before using it.
The function’s returned string can be embedded in a JSON payload for schema publication.
A common automation use is sending printed SDL to a schema registry.
The schema argument is the value serialized by the function.

Common mistakes

The printed SDL is text suitable for publishing, but registry workflows may also require version metadata.

Example: Print a schema as SDL

import { buildSchema, printSchema } from "graphql";

const schema = buildSchema(`
  type Query {
    greeting: String!
  }
`);

console.log(printSchema(schema));

Builds a schema and prints its SDL representation.

When to use it

Registry publication

Publish the current API contract to a schema registry.

Automation

Generate SDL text for governance or CI workflows.

Schema artifacts

Create a human-readable schema artifact for tooling.

Interview questions

QWhat does printSchema do?

It produces the schema definition in GraphQL SDL form from a schema object. The printed result can then be sent to a schema registry or another SDL-based tool.

Follow-up: Why might a team publish this output? A registry can use the SDL as the service’s versioned schema representation.

QHow is printSchema used in a registry-publishing workflow?

Call it with the GraphQL schema as its argument, then use the returned string as the request body or file content. The official example passes that string to a registry’s schema-publish endpoint.

Follow-up: What additional information might accompany the SDL? The example includes a separate version value in the published JSON payload.

QWhy is printSchema useful for tooling?

It serializes the schema into SDL rather than executing a query or discovering data at runtime. This makes the output useful for automation and governance tooling.

Follow-up: What should be checked before publishing? Validate that the schema object represents the intended API and attach the correct release metadata.

GraphQL schema
schema registry
SDL
version metadata

Source: Tooling and Automation for Governance - GraphQL. Checked 2026-10-15.