Playwright-graphql: Revolutionize GraphQL Testing with Auto-Generated Type-Safe Client

Playwright-graphql changes how we test GraphQL APIs. It creates client SDKs from your GraphQL schema, removing the need to write queries by hand. This tool combines Playwright's testing power with GraphQL's flexibility, making tests easier to write and maintain.

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Before diving into GraphQL client-based automated tests, let me share a brief story about why I decided to build this integration.

When I first encountered a GraphQL API at work, I did what any engineer would do when faced with something unfamiliar, I googled it. I searched for "How to automate GraphQL with Playwright." The results, were disappointing. Every solution from seemingly relevant sources relied on using queries and mutations as raw strings in the codebase or, at best, employed rudimentary string builders.

This approach felt wrong. It was clunky, error-prone, and missed a critical point about how GraphQL APIs work under the hood. Let’s explore why this is a common mistake and how Playwright-GraphQL solves it.

The Problem with String-Based GraphQL Operations

To understand why using raw strings for GraphQL operations is problematic, we first need to understand how GraphQL APIs work behind the scenes.

How GraphQL Works:

GraphQL servers convert your queries into SQL queries, and mutations into CREATE, UPDATE, or DELETE operations in the database. For example:

{
        location(locationId:1428){
          id
          name
          created
        }
 }

Will be transformed into:

SELECT id, name, created FROM locations WHERE id = 1428;

The power of GraphQL lies in its flexibility. It allows developers to request only the data they need. However, this flexibility comes with a responsibility: ensuring that input parameters (like locationId) are tested thoroughly. Why? Because input parameters drive the backend logic (e.g., SQL WHERE conditions), while query fields (like id, name, created) just define which properties are selected in the response.

The Real Goal of GraphQL Testing

The primary goal of GraphQL testing should be to validate how input parameters affect backend behaviour. For example:

• Are filters applied correctly?
• Are limits (take) and offsets (skip) handled properly?
• Does data in response sorted as expected?
• Does the API return the expected results for edge cases?

Focusing on query fields instead of input parameters is a mistake because query fields don’t affect backend logic they only control what’s added in the response. To effectively test a GraphQL API:

1. Maximize SQL Query Coverage: Ensure your tests trigger as many variations of SQL WHERE conditions as possible.
2. Avoid Overloading Queries: Keep parameters like take (used for limiting results) reasonable to avoid extracting excessive data.

How Playwright-GraphQL Solves This Problem

Playwright-GraphQL eliminates the need for raw strings in your codebase by generating type-safe operations directly from your GraphQL schema. This approach ensures:

1. Focus on Input Parameters: Tests validate how input parameters affect backend logic.
2. Readable Tests: Tests focus on what is being tested, not how it is being tested.
3. Type Safety: Auto-generated types prevent invalid queries or mutations.

Here’s an example: Without playwright-graphql:

Here's how this same test looks when using playwright-graphql:

Why Playwright-GraphQL is Better:

1. No Raw Strings: You no longer need to write raw GraphQL queries or manually manage variables.
2. Type Safety: The generated client ensures that only valid operations and parameters can be used.
3. Cleaner Assertions: The response is already parsed and structured, so you can directly assert on the returned data.

By using Playwright-GraphQL, you avoid common pitfalls like forgetting to parse the JSON payload or misnaming fields in your queries. It simplifies your tests and allows you to focus on validating business logic instead of worrying about GraphQL protocol details.

🔑 Main Feature: Schema-Driven Automation

Unlike other GraphQL testing methods, this tool makes complete client SDKs directly from your GraphQL schema:

How It Works

1. Get Schema get-graphql-schema pulls your GraphQL endpoint definition
2. Make Operations gql-generator creates all possible queries/mutations
3. Add TypeScript GraphQL Codegen makes fully-typed client methods with autocomplete

NPM Package: https://www.npmjs.com/package/playwright-graphql

Template repo: https://github.com/DanteUkraine/playwright-graphql-example

Playwright-graphql makes GraphQL testing easier. It creates your API client automatically, so you can focus on writing good tests instead of managing API details. This saves time and helps catch errors early.