Key Considerations for Migrating to GraphQL

While our GraphQL API delivers significant benefits - such as faster page loads, reduced data usage, and improved developer control - migrating from our legacy APIs requires a shift in how your team interacts with our platform. This section outlines the key differences in development practices to support a smooth transition.

From “Endpoints” to a “Single Data Contract”

The most fundamental change is moving from REST’s resource-centric model to GraphQL’s schema-driven approach.

REST API Approach	GraphQL Approach	Impact on Your Application
Fixed Resources (Endpoints)	Flexible Data Graph (Schema)	Faster Feature Development. You define the data structure and dependencies you need, enabling rapid iteration without waiting for new endpoints.
Multiple Calls Required	One Query, All Data	Fewer Round Trips. Fetch related data - such as user details, orders, and line items - in a single request, reducing latency.
Fixed Data Payloads	Select Only What You Need	Efficiency Gains. Request only the fields your app uses, resulting in smaller payloads and better performance, especially on mobile.

Developer takeaway: Your team will shift from calling specific URLs (e.g. /products/123) to crafting precise queries that describe the exact data needed for each view.

A Change in Developer Tooling and Workflow

GraphQL supports structured approaches to debugging, testing, and error handling, with a robust ecosystem of tools and best practices to assist developers.

REST API Workflow	GraphQL Workflow	Required Developer Action
Testing with Postman / cURL	Testing with GraphiQL / Apollo Explorer	Use our in-browser GraphQL IDE for autocomplete, schema inspection, and live query testing.
Error Checking via HTTP Status Codes	Error Checking via Response Body	Update logic to parse the errors field in the response, as GraphQL always returns `200 OK`.
Call-Based Rate Limiting	Cost-Based Rate Limiting	Optimise queries based on complexity scores. Learn to inspect query cost to stay within usage budgets.

Developer takeaway: GraphQL’s introspective schema and tooling ecosystem streamline development, but require updated error handling and query optimisation strategies.

Strategy for a Seamless Migration

To minimise disruption, we recommend an incremental, hybrid approach:

Start with New Features: Build new screens and features using GraphQL to gain experience without affecting stable code.
Use a Hybrid Architecture: Run REST and GraphQL side-by-side. For example, keep legacy REST powering the existing reports while GraphQL handles a new reporting page.
Adopt Client-Side Caching: Because GraphQL uses a single endpoint, standard browser caching is less effective. Use tools like Apollo Client or Relay to manage caching and state efficiently.

Developer takeaway: Migration doesn’t require a full rewrite. You can adopt GraphQL gradually, starting with new use cases and integrating caching tools to maintain performance.

Benefits of Migrating

Feature	REST	GraphQL
Multiple Calls	Yes	No
Manual Data Join	Yes	No
Field Selection	Fixed	Flexible
Performance	Slower	Faster
Script Complexity	High	Low