Graphql

GraphQL is an open-source query language and server-side runtime for APIs. Instead of hitting multiple fixed endpoints and hoping for the right data, you write a query that describes exactly what you need — and the server responds with a matching JSON object. That means no over-fetching a huge response when all you want is a name, and no under-fetching that forces a second request. GraphQL uses a strongly-typed schema to define every data type and relationship in your API, so both clients and servers know exactly what's available and what format to expect.

How does it work? You define a schema using GraphQL's type system — think of it as a contract between frontend and backend. Then clients send queries that mirror the shape of the response they want. For example, a query for a city's population and weather returns only those fields, nothing extra. The runtime processes the query, validates it against the schema, and executes the necessary data fetching. Because GraphQL is database-agnostic, it works with your existing code and storage. The tool also supports real-time subscriptions, mutations for writing data, and introspection — the ability for the API to describe itself. This self-documenting nature powers tools like GraphiQL, an interactive in-browser IDE for testing queries.

Who should use GraphQL? Any team building or consuming APIs — especially those with complex data relationships, mobile apps where bandwidth matters, or microservices architectures. Frontend developers love it because they control exactly what data the UI receives. Backend developers appreciate the clear schema and the ability to evolve APIs without versioning. Large companies like Meta, Airbnb, and Shopify rely on it for production. If your app needs to fetch nested data efficiently (think a social media feed with user profiles, posts, and comments), GraphQL turns multiple round-trips into one precise request.