A Complete Guide to Creating Custom GraphQL in Magento 2

• Why Do You Need to Use GraphQL in Magento 2?

• Why is GraphQL Ideal for Magento Developers?

• Core Operations of the GraphQL Module in Magento 2

• Advanced Features For Creating a Custom GraphQL in Magento

• Use Cases and Components of GraphQL Modules in Magento 2

• GraphQL Custom Module Capabilities in Magento

• GraphQL API Roadmap

• GraphQL Request in Magento: Limitations and Missing Features

• How to Optimize Your Magento 2 Store’s Performance with Custom Query Modules?

• 6 Steps to Create Custom GraphQL Endpoints in Magento

• Why Do You Need to Create Custom Queries and Mutations in Magento?

• 7 Steps to Use GraphQL Queries to Fetch Customer Data

• 6 Steps to Create a GraphQL Mutation in Magento 2

• Best Practices for Managing Data by Query and Write Operations in Custom GraphQL

• Why Choose GraphQL for Complex Magento Operations?

• Troubleshooting Custom GraphQL: Using Third-Party Tools and Libraries for Effective Debugging

• FAQs

• Summary

Why Do You Need to Use GraphQL in Magento 2?

GraphQL is a query language for APIs that serves as a modern alternative to REST and SOAP APIs.

GraphQL allows you to build Progressive Web Applications (PWAs). For instance, you can integrate it with the official PWA Studio to improve API efficiency. This toolkit simplifies PWA development and includes ready-made GraphQL solutions. It enables faster, more efficient front-end development.

Why is GraphQL Ideal for Magento Developers?

Developers prefer GraphQL because it reduces server load. It fetches only the required data fields. It makes it a perfect fit for Magento's complex architecture. It enhances flexibility, speeds up APIs, and optimizes performance. Compared to traditional REST & SOAP methods, most of the core functionality is available. It offers the following benefits to the Magento 2 developers:

1. Efficient Data Retrieval: Developers can request only the specific data they need. It minimizes unnecessary data transfer. This efficiency is particularly valuable for mobile applications and low-bandwidth environments.

2. Flexible Data Model: Developers can query data naturally and intuitively. This flexibility simplifies the development of complex, data-driven applications.

3. User-Friendly Syntax: GraphQL’s straightforward and intuitive syntax reduces the learning curve. Developers can adopt it and build applications rather than learning intricate API structures.

4. Customizability: Developers can create custom queries, mutations, & types to extend the default schema. This customization enables tailored functionality to meet unique business needs.

5. Optimized Queries: GraphQL reduces the number of API calls. It allows developers to fetch all required data in a single query. This optimization improves application performance and ensures faster response times.

Core Operations of the GraphQL Module in Magento 2

GraphQL is a data query language that supports three primary operations:

1. Queries: Used for reading and fetching data.

2. Mutations: Enable actions like creating modifying data (e.g., updating a customer's email).

3. Subscriptions: Subscriptions allow real-time updates from the server, such as automatic notifications.

Advanced Features For Creating a Custom GraphQL in Magento

1. Performance Optimization Techniques

• Implement hybrid filtering to combine JCR and AEM filtering.
• Use cursor-based pagination for large datasets.
• Minimize fragment nesting (keep it under "5-6 levels").
• Use data loaders to batch requests.
• Limit query depth to stop those pesky data overloads.

2. Enhanced Type System

• Input Types: Define specific data structures for mutations.
• Enum Types: Create fixed sets of values.
• Interface Types: Share common fields between different types.

3. Query Optimization Strategies

• Use field-specific resolvers.
• Implement batch loading for related data.
• Cache frequently accessed queries.

4. Advanced Error Handling

• Keep mutations separate from queries.
• Use clear, descriptive field names.
• Implement proper type validation.

Use Cases and Components of GraphQL Modules in Magento 2

Core Module	Primary Function	Use Case
CatalogGraphQl	Manages product catalog operations	Handles product listings, searches, and catalog data queries
CustomerGraphQl	Handles customer-related operations	Manages customer accounts, authentication, and profile data
CatalogInventoryGraphQl	Controls inventory management	Tracks stock levels and inventory updates
BundleGraphQl	Manages bundle products	Handles complex product combinations and pricing
ConfigurableProductGraphQl	Handles configurable products	Manages products with multiple options (size, color, etc.)
DownloadableGraphQl	Manages downloadable products	Handles digital product delivery and access
EavGraphQl	Controls entity-attribute-value operations	Manage custom attributes and values
GroupedProductGraphQl	Handles grouped products	Manages sets of related products sold individually
TaxGraphQl	Manages tax calculations	Handles tax rules and calculations
ThemeGraphQl	Controls store theming	Manages store appearance and layout
UrlRewriteGraphQl	Handles URL management	Manages URL rewrites and redirects
WeeeGraphQl	Manages waste electrical equipment tax	Handles special tax calculations for electronic items
CatalogUrlRewriteGraphQl	Controls catalog-specific URLs	Manages product and category URL structures

GraphQL Custom Module Capabilities in Magento

• Support for all product types.
• Integration with default payment methods, including PayPal, Bank Transfer, Braintree, and more.
• Compatibility with various shipping methods.
• Enhanced layered navigation with improved features and updated design.
• Achieved a response time of under "0.5 seconds", even with "500 simultaneous requests".
• Functionality to manage reorder scenarios.
• Ability to save payment tokens for card payments.
• Access to logged-in customers' order histories.
• Information on gift messages and gift wrapping options.
• Features for managing diverse inventory scenarios.
• A single mutation capable of processing all product types.
• Wishlist and customer review functionalities.
• Ideal for building PWAs with tools like Magento PWA Studio.
• Efficient replacement of REST and SOAP by handling specific queries with ease.
• Supports queries and mutations, with future potential for real-time updates via subscriptions.

GraphQL API Roadmap

The roadmap focuses on addressing existing gaps. It aims to enhance functionality for both B2C and advanced use cases. Alongside bug fixes, developers focus on the following:

• Reorder functionality for managing repeat purchases.
• Support for preferred payment methods saved by customers.
• Access to order history for logged-in customers.
• Features for managing gift messages and packaging options.
• Enhanced inventory management for in-store item collection.

GraphQL Request in Magento: Limitations and Missing Features

1. GraphQL Module Compatibility

Many third-party vendors focus on making their modules GraphQL-compatible. But, these APIs are often subpar, making custom development a better option. Modules without custom GraphQL support will need to be built from scratch. It requires additional coding and frontend work for PWA themes.

2. Missing Features

Certain features, such as file uploading, are not supported in GraphQL. Unlike REST API in Magento 2, developers must create custom solutions for these tasks. It allows you to handle various content types.

3. Offline Functionality

GraphQL lacks built-in support for network caching, which limits offline capabilities. When building PWAs, developers need to configure offline functionality. They need to focus on the client side to address this limitation.

4. Complex Schema Maintenance

Managing a large & intricate GraphQL schema can be challenging, particularly for extensive APIs. However, experienced developers can successfully handle these complexities in Magento projects.

How to Optimize Your Magento 2 Store’s Performance with Custom Query Modules?

1. Add Pagination: Enable fetching multiple reviews with pagination controls.
2. Cache Responses: Use the @cache directive to improve performance for frequently accessed queries.
3. Additional Fields: Extend the ReviewData type to include more details. Examples include ratings or review status.
4. Secure Queries: Add authentication to restrict access to sensitive data.
5. Validation: Add checks for input values (e.g., ensuring newQuantity is positive).
6. Caching: Implement caching for frequently updated data to optimize performance.
7. Authorization: Restrict access to the mutation to authorized users or roles.
8. Extensibility: Allow adding more fields to the input or output types as needed.
9. Error Logging: Log exceptions for easier debugging and monitoring.

6 Steps to Create Custom GraphQL Endpoints in Magento

1. Create the module registration file.

File: registration.php Path: app/code/Vendor/CustomGraphQL/registration.php

2. Define the module in module.xml.

File: module.xml Path: app/code/Vendor/CustomGraphQL/etc/module.xml

The <module_name>/etc/schema.graphqls file serves the following purposes:

• Specifies the structure of queries and mutations.
• Defines the input and output attributes available for GraphQL queries and mutations.
• Separates valid features for requests and responses.
• Links to resolvers that validate and process input data and generate responses.
• Acts as the source for displaying the schema in GraphQL browsers.
• Determines which objects should be cached.

3. Define the GraphQL Schema.

File: schema.graphqls Path: app/code/Vendor/CustomGraphQL/etc/schema.graphqls

4. Create the resolver.

File: ProductResolver.php Path: app/code/Vendor/CustomGraphQL/Model/Resolver/ProductResolver.php

5. Create a controller to take care of GraphQL requests and route them to your schema.

Note: In Magento, GraphQL requests can be made using both HTTP GET and POST methods. However, mutations must be sent using the POST method. Optionally, you can send a GET query request directly through the URL.

6. Test your custom GraphQL query. You can test it using tools like Altair GraphQL Client or Postman.

Note: The GraphQL endpoint in Magento 2 is located at /graphql. To interact with it, use the following URL structure: http://<magento2-server>/graphql.

Why Do You Need to Create Custom Queries and Mutations in Magento?

In GraphQL, mutations are request types designed to modify data. They allow you to create, update, or delete objects and fields. Queries in the GraphQL function are similar to GET requests in REST. Mutations correspond to operations like POST, PUT, and DELETE.

In Magento GraphQL, mutations provide enhanced functionality for managing data. They can be used to create new entities, update existing records, or remove data. For instance, mutations enable actions such as:

• Creating a customer account
• Adding a product to a cart
• Updating order statuses
• Deleting customer records

7 Steps to Use GraphQL Queries to Fetch Customer Data

1. Create and name your module Vendor/GraphQl.
2. Ensure it is loaded after the GraphQL and Customer modules by defining dependencies.
3. Define the schema in the file schema.graphqls located at:

vendor/module/etc/schema.graphqls

Consider the following key considerations:

• Identify the data fields and their types (e.g., "String", "Int", "Float").

• Ensure you understand how this data will be used in your application. For example, frontend display or API integration.

To configure this, check the key elements below:

• type Query: Declares the query operation for the module.
• lastProductReview: Custom query name that accepts a product ID as a required parameter.
• testCustomer: Name of the query.
• email: String!: Input parameter for the query, specifying the email address.
• @resolver: Specifies the class that resolves the query.
• ReviewData: Defines the structure of the query response. Examples include fields like review_id, title, and nickname.
• @cache: Indicates whether the result is cacheable (false in this case). For example, queries related to products, categories, and CMS content can be cached.

Note: The cache identity value specifies the class responsible for retrieving cache tags. Queries without a defined cache identity will not be cached.

• type TestCustomer: Defines the structure of the query result. Examples include customer fields like firstName, lastName, and email.

4. Create a resolver class to handle the query logic.
5. Path: app/code/Vendor/GraphQl/Model/Resolver/Customer.php

Note:

• The resolver class must implement Magento\Framework\GraphQl\Query\ResolverInterface.
• The resolve method processes the query, with $args containing the input parameters.
• Use Magento's exception classes like GraphQlNoSuchEntityException to handle errors.

To test the query, use a Chrome extension like ChromeiQL or Postman:

6. Set the endpoint to <Magento root URL>/graphql.
7. Execute the query and review the response.

To test and verify, consider the following:

• Hire experienced Magento developers for complex testing or customization.
• Use ChromeiQL or similar tools to verify queries and responses quickly.
• Always validate inputs and handle errors gracefully in your resolver logic.

6 Steps to Create a GraphQL Mutation in Magento 2

Step 1: Define Your Mutation

Mutations in GraphQL are used to create, update, or delete data. Identify the specific data modifications your mutation will handle & the required input parameters.

The API response enables developers to create custom applications or integrations. However, unexpected behavior can occur with custom responses. For instance, when a "price" is provided as an input filter, Magento interprets it as a 'Float' value.

In the schema.graphqls file, the output interface defines the top-level attributes. Each attribute's data type—whether scalar, object, or array—must be explicitly specified.

Note: Each type definition includes the input, output, & sorting attributes of an object. You can specify attributes that serve as inputs for executing module operations.

Step 2: Use Annotations

Annotations allow you to add descriptions to attributes, type definitions, or entities. You can include them within a schema.graphqls file. These descriptions provide additional context or information about the schema. You can append annotations in the following format:

@doc(description: "<Text>")

Check the example below:

SKU: FilterTypeInput @doc(description: "A number or code assigned to a product to identify the product, options, price, etc.")

Step 3: Create the Schema File

The schema file defines the mutation, its input, and its output types.

File: schema.graphqls Path: app/code/Vendor/Module/etc/schema.graphqls

Consider the following key elements:

• type Mutation: Declares the mutation operation.
• updateProductQuantity: Name of the mutation.
• input: Specifies the input type (UpdateProductQuantityInput) required for the mutation.
• type UpdateProductQuantityOutput: Defines the structure of the mutation's response. For example, whether the operation was successful and a message.

Step 4: Implement the Resolver

The resolver contains the logic for handling the mutation & performing the desired changes. They are implemented as PHP classes and can be organized in a dedicated directory. For example, Model/Resolver.

File: UpdateProductQuantity.php Path: app/code/Vendor/Module/Model/Resolver/UpdateProductQuantity.php

Step 5: Execute the Required Commands

To activate your module & clear the cache, run the below commands from the Magento 2 root directory:

bin/magento setup:upgrade bin/magento setup:di:compile bin/magento cache:clean

Step 6: Test Your Custom Mutation

Testing ensures your mutation functions correctly and makes the intended changes. Use a GraphQL client like Altair GraphQL Client or Postman to test.

Best Practices for Managing Data by Query and Write Operations in Custom GraphQL

Operation Type	Best Practice	Implementation Details	Impact
Query Operations	- Input Validation - Query Depth Limiting - Query Complexity Control - Field-Level Resolution	- Implement strict validation rules for all incoming queries. - Set the maximum depth to "20 nodes". - Limit complexity score to "300". - Use specific resolvers for each field.	- Prevents injection attacks and data corruption - Prevents Improves query efficiency - Prevents DDoS attacks - Improves Improves query efficiency
Write Operations	- Batched Processing - Data Sanitization - Transaction Management	- Combine multiple mutations into single requests. - Clean and validate all input data. - Implement atomic operations.	- Reduces server load - Prevents security vulnerabilities - Ensures data consistency
Performance	- Caching Strategy - Query Optimization - Pagination Implementation	- Cache frequently accessed queries. - Use field-specific resolvers. - Limit result set size.	- Reduces response time - Improves execution speed - Manages large datasets efficiently
Security	- Authentication - Authorization - Introspection Control	- Implement token-based auth. - Use field-level permissions. - Disable in production.	- Secures endpoints - Controls data access - Reduces attack surface
Monitoring	- Performance Tracking - Error Logging	- Implement query analysis tools. - Set up detailed logging.	- Identifies bottlenecks - Aids troubleshooting

Why Choose GraphQL for Complex Magento Operations?

1. Flexibility in Data Retrieval

Developers can request the exact data they need. It eliminates the limitations of fixed data structures found in REST APIs.

• Instead of multiple API calls, GraphQL consolidates data retrieval into a single query. It saves time and resources.

• Modify responses to match specific application needs. It reduces unnecessary data transfer and simplifies API management.

This flexibility enhances development and ensures the application fetches what it requires. It makes it ideal for dynamic use cases.

2. Improved Efficiency

GraphQL resolves common inefficiencies associated with REST APIs. For example, over-fetching or under-fetching data.

• Optimized Queries: Request only the fields your application needs. It reduces data payloads and bandwidth usage.

• Faster Load Times: By avoiding excessive data transfers, GraphQL improves response times. It is beneficial for applications pulling data from multiple sources.

For complex applications with high data demands, ensure enhanced performance & optimal resource utilization.

3. Scalability for Growing Businesses

As your business grows, so do your API requirements. GraphQL’s schema-driven approach supports effortless scalability.

• Extendable Schemas: Add new fields, data types, or functionality without breaking existing queries.

• Deprecation Support: Safely phase out older API elements while maintaining backward compatibility.

GraphQL ensures your APIs evolve alongside your business. It offers a future-proof solution for scaling eCommerce operations.

4. Enhanced Developer Experience

GraphQL’s intuitive design and enhanced tooling simplify the development process. This makes it a developer-friendly choice.

• Strong Typing: The schema defines types for every field. It provides real-time feedback and validation during development.

• Easier Debugging: Developers receive precise error messages, which reduces troubleshooting time.

• Optimized Workflow: Consolidated queries and simplified endpoint management improve productivity in large-scale projects.

This enhanced experience leads to faster development cycles and fewer integration errors.

5. Optimized Performance for Mobile and Web Applications

In mobile and web environments where performance is vital, GraphQL delivers superior results.

• Bandwidth Optimization: Minimize data loads by requesting only necessary fields. It is especially beneficial for mobile devices with limited connectivity.

• Reduced Network Requests: GraphQL combines data from multiple resources in a single request. It improves performance for web and mobile applications.

These features ensure a smooth, responsive user experience across all devices. It makes GraphQL a key asset for customer-centric platforms.

6. Versatility for Custom Development

GraphQL’s adaptability makes it suitable for various custom eCommerce functionalities:

• Multi-Layered Integrations: Connect multiple data sources within a single query.

• Advanced Search and Filters: Build detailed search functionalities by leveraging complex query structures.

• Dynamic Frontends: Support headless commerce models. They serve as an enhanced API layer for PWAs or mobile applications.

This versatility empowers developers to create feature-rich, high-performance solutions for unique business requirements.

Troubleshooting Custom GraphQL: Using Third-Party Tools and Libraries for Effective Debugging

Tool/Library	Primary Function	Use Case	Debugging Capability
GraphiQL	Query Testing & Exploration	Interactive query testing	Real-time query validation and response inspection
Xdebug with PhpStorm	PHP Execution Debugging	Backend resolver debugging	Step-by-step code execution analysis
Apollo Client DevTools	Frontend Debugging	Client-side query monitoring	Cache inspection and query-watching
GraphQL Playground	API Testing	Schema exploration and testing	Documentation browsing and query history.
Altair GraphQL Client	Advanced Query Testing	Complex query debugging	Multi-environment testing and request history.
Chrome DevTools Network	Network Analysis	Performance monitoring	Request/response inspection and timing analysis.
Field-Level Resolvers	Performance Debugging	Query optimization	Identifying "N+1" query problems.
GraphQL Yoga	Server Testing	Backend validation	Schema validation and error catching.
Query Analyzers	Performance Optimization	Query efficiency testing	Over-fetching and under-fetching detection.
Monitoring Tools	Performance Tracking	Production debugging	Real-time performance metrics and alerts.

FAQs

1. What is GraphQL, and why does Magento use it?

GraphQL provides a flexible query language for APIs, which improves its performance. It lets developers request specific data through queries. The system returns only requested information, which reduces server load significantly.

2. How can I create custom GraphQL queries in Magento?

Use MagentoFrameworkGraphQLConfig ElementField to define query structure and implement ResolverInterface for query processing. Add TypeResolverInfo for data type handling. Follow Magento's module structure guidelines to create resolver class files.

3. What are the main GraphQL exceptions in Magento?

GraphQLInputException handles invalid input data problems, and GraphQLNoSuchEntityException manages missing entity errors. While GraphQLAuthorizationException controls access issues, LocalizedException deals with localization problems.

4. How does GraphQL query resolution work in Magento?

ResolverInterface processes incoming GraphQL queries as ResolverValue handles data transformation. ResolverValueFactory creates response objects, and the Context interface manages the query state.

5. What role does CustomerFactory play in GraphQL queries?

CustomerFactory creates customer model instances. It works with CustomerRepositoryInterface for data access. While CustomerInterface defines data structure standards, OutputProcessor formats response data.

6. How can I handle GraphQL navigation in custom modules?

Create a resolver class in your module and implement ResolverIdentityInterface for proper navigation. Define query paths clearly to set up resolver logic.

7. What are GraphQL-type safety features in Magento?

Type definitions prevent incorrect data submissions. With schema validation, you can catch query errors early. While input validation improves data quality, type resolvers maintain data consistency.

Summary

Custom GraphQL in Magento 2 lets you modify GraphQL queries to suit specific needs. It allows you to:

• Optimize your API performance while maintaining flexibility.
• Build custom GraphQL functionality for your Magento store.
• Simplify your store's API management with custom GraphQL queries.
• Get access to Magento's CLI to run commands.
• Create custom GraphQL queries in your Magento 2 store environment.
• Improve how data is requested and displayed in Magento 2.

Consider Magento hosting services to simplify your store's API management with custom GraphQL.