Debunking common misconceptions

Before we can compare using REST and GraphQL to power your decoupled or headless application, we need to address several common misconceptions that arise in the context of WordPress. Some of these arise from conflating implementing an API vs consuming one. Others are based on outdated information, a frequent occurrence in the fast-paced, headless WordPress ecosystem. Regardless of why, it’s time to put them to rest.

API performance

Concern: Businesses might be concerned that one API may significantly outperform the other, impacting user experience and system efficiency. As we noted above, reliance on REST APIs often results in overfetching, while designing performant GraphQL schemas require thought and skill. GraphQL also gets a bad reputation for being harder to cache, since it doesn’t have resource specific endpoints.

The reality: As a platform powering a large portion of the web, both the WordPress REST API and WPGraphQL take performance into account. 

The REST API’s support for field selection and batch queries help prevent overfetching and multiple trips to the server by grouping requests together and limiting the data returned. While REST doesn’t offer the full granularity of GraphQL, these features can make the differences marginal in most cases. 

Meanwhile, WPGraphQL (WordPress GraphQL) implements performant patterns such as DataLoaders and cursor-based Connections, which puts the complexity of schema design on par with the WordPress Rest API. Frontend support for GraphQL GET requests coupled with an extension like WPGraphQL Smart Cache can even lead to better and more nuanced caching strategies – and more performant responses – than the WordPress REST API with its own caching layer; it just requires a bit more to set up.

GraphQL’s flexible query language, while a huge advantage over REST, comes with its own performance risk: it’s really easy to request complex sets of data. Care should be taken to only query for data you need, when you need it, using features like reusable fragments, cursor-based pagination, and sensible connections when composing your GraphQL queries.

The practical difference: If your application only requires handling simple data requirements that are mostly represented by WordPress’s object structure, the WordPress REST API – when combined with “_fields” and batch queries – will likely be the most performant and easiest to optimize against.

If, on the other hand, you’re building complex data views composed of different WordPress objects such as those needed to power a headless CMS, GraphQL’s ability to fine-tune data requests could make it the better choice—provided your team has the expertise to configure it and use its query language effectively.

API security

Concern: There may be concerns that one API offers superior security features, making it a safer choice for protecting sensitive data. A particularly common misconception is that REST is inherently more secure than GraphQL since REST can make use of the security and authentication built into the HTTP protocol, while GraphQL doesn’t have a native security or authentication layer.

The reality: Both REST and GraphQL in WordPress incorporate robust security layers leveraging user roles and capabilities, and can be made secure with proper configuration that requires the same amount of effort – and near-identical techniques – for each API. Additionally, numerous plugins exist for both APIs to facilitate headless authentication using methods like JSON Web Tokens (JWT), native WordPress cookies, OAuth2, and more. 

The practical difference: Since both APIs can handle authentications and permissions effectively, the choice between them should focus more on other implementation needs. It should be noted that since REST is closely integrated with core WordPress features, the “out-of-the-box” implementation may meet the needs of simpler projects with less configuration.

API compatibility

Concern: Companies might worry about long-term compatibility and maintenance, fearing that one API could introduce more breaking changes or be harder to support as their system evolves. A common misconception is that REST is less future-compatible since endpoints are usually versioned, while GraphQL schemas are designed to be versionless.

The reality: WordPress’s commitment to backward compatibility means that REST endpoints are versioned rarely and deliberately, and even when they are, the old endpoints remain providing your decoupled project time to migrate. However, the lack of type safety in WordPress’s REST API means you still must guard around “non-versioned” breaking changes that can occur on some core WordPress APIs or as a result of customizations from other plugins.

Conversely, the active development within the GraphQL ecosystem may occasionally introduce breaking changes, despite GraphQL’s schema design principles aiming for future compatibility. This can be especially true when relying on community extensions. However, breaking changes are easier to identify and prevent due to the built in type-safety of the schema.

The practical difference: For straightforward projects with a simple and controlled plugin stack, the WordPress REST API might be the more stable choice that requires less ongoing maintenance to keep compatible with WordPress’s latest. However, GraphQL’s type-safe schema makes it easy to prevent shipping breaking changes and update your code for compatibility, which are invaluable in a complex stack or an application with an ongoing development cycle.

API implementation

Concern: A common belief is that it’s easier to implement REST APIs than define a GraphQL schema. Since REST is just a collection of endpoints returning a simple JSON payload, teams don’t need to spend time defining custom GraphQL types or thinking about performant data models.

The reality: Thanks to the WordPress REST API and WPGraphQL, the amount of custom API design is already fairly minimal, and the robust Developer APIs for both make the process of exposing custom data easy regardless of which one you choose. Instead, the two APIs differ on where in the design/implementation process the complexity lies. REST’s untyped nature makes it easy to scaffold an endpoint without much forethought. Additional care must be taken when consuming the response data, as well as that your custom endpoints aren’t too coupled to your frontend use case. Similarly, WPGraphQL requires you to consider your schema design upfront and understand efficient data loading patterns; while a lack of consideration for these concerns when developing custom REST endpoint will result in long-term issues for your team and application, they aren’t strictly required.

The practical difference: If your project involves straightforward data interactions and you prefer flexibility in implementation, REST might be the better choice. However, for projects requiring complex, type-safe data exchanges, WPGraphQL could reduce long-term complexity and errors, ultimately saving time and resources.

Additional Pros and Cons

Not all common arguments in favor of WPGraphQL versus the WordPress REST API are invalid. Here are some more differences between the two APIs you should consider before choosing which is best for your decoupled/headless use case.

• Learning Curve: As a query language, GraphQL has a much higher learning curve, since you need to take care to craft smart and performant queries. REST forces you to write simple queries, since every endpoint is just a dump of predefined values.
• Developer Experience:  GraphQL often offers a superior developer experience due to its strictly typed schema, enabling powerful tools like WPGraphiQL Explorer and GraphQL Voyager, which are particularly beneficial in headless or decoupled CMS projects. The WordPress REST API allows you to “hint” a schema, but it does not enforce it, leading to potential bugs, edge cases, and overall increased tech debt.
• Stack Fragility: The WordPress REST API is an integral part of WordPress and implemented by most plugins – at least to an extent. Meanwhile, WPGraphQL is an external plugin and a collection of third-party extensions, each with differing levels of code quality and support. That extra fragility represents a significant risk of assumed tech debt from potential bugs and plugin updates.

Choosing the right API

Benefits of REST API 

Consider the WordPress REST API when –  

• Your data needs are simple and already exposed via WordPress core or plugins.
• Your use case for a decoupled application is straightforward, and wouldn’t benefit from robust DX or type validation.
• You need to rapidly prototype APIs during development.
• Your team is already familiar with WordPress’s REST APIs or Gutenberg.
• Your “backend” tech debt costs, such as managing WordPress plugins and debugging PHP code, are lower than your “frontend” costs, such as component/UX design and frontend development.

Benefits of WordPress GraphQL – 

Opt for WPGraphQL when – 

• Your frontend interfaces rely on complex data structures and custom UX.
• You need to maintain a “separation of concerns” between backend and frontend knowledge, such as a React frontend team that can work independently of a “WordPress/PHP” team. 
• You need to expose the same data for multiple scenarios or user experiences, such as custom web views, or Mobile and IoT applications.
• You need robust developer tools and type validation in your IDE tool.
• Your frontend development team is already familiar with GraphQL’s query language.

No one-size-fits-all solution

As with any technology decision, the key is to remain adaptable. The decision between GraphQL vs REST API is not a one-size-fits-all. It depends on your project’s specific needs, team expertise, and long-term goals. Carefully weigh the pros and cons of each API approach while implementing a headless or decoupled architecture and contact us to make an informed decision.