Different Types Of API For Web Development 2022

Quick answer. APIs for web development are grouped three ways: by access policy (open, partner, internal, composite), by protocol or architecture (REST, SOAP, GraphQL, gRPC, WebSocket, webhook, RPC), and by the system they serve (database, operating system, remote, web). REST stays the default for most web and mobile apps in 2026, with GraphQL, gRPC and WebSocket handling more specialised needs.

Choosing the right type of API is one of the earliest architecture decisions in any web project, and it shapes performance, security and how easily other teams can build on top of your services. Over the years APIs have grown far more sophisticated, so it helps to break them into clear categories before you commit to one.

An application programming interface (API) is a contract that defines how two pieces of software talk to each other — the requests you can make, how to make them, the data formats to use, and the conventions to follow. This guide walks through the main types of API used in web development in 2026 and when each one is the right fit.

How are APIs classified?

There is no single “list” of API types, because APIs can be sorted along three different axes at once. The same REST endpoint can be a public API by access policy, a REST API by protocol, and a web API by use case. Understanding all three views prevents the confusion that comes from treating them as one flat list.

• By access policy — who is allowed to call the API: open, partner, internal, or composite.
• By protocol and architecture — the technical style of communication: REST, SOAP, GraphQL, gRPC, WebSocket, webhook, or RPC.
• By use case — the system the API talks to: database, operating system, remote, or web.

Types of APIs by access policy

The first way to classify APIs is by who can use them and under what terms. There are four main categories.

1. Open APIs (public APIs) — publicly available to any developer with minimal restriction. They may require registration, an API key, or OAuth, or be completely open. They are designed for external consumers who want to access your data or services.
2. Partner APIs — exposed only to specific business partners under an agreement. They are not public: access usually goes through an onboarding process with a validation workflow, often via a partner developer portal. They let companies collaborate beyond their own boundaries while keeping control over who connects.
3. Internal APIs (private APIs) — hidden from external users and consumed only by systems inside the organisation. They exist to help internal teams reuse services and move faster, and are typically protected by the company’s identity and access management (IAM) systems.
4. Composite APIs — combine several data or service calls into a single request. They let a client hit multiple endpoints in one round trip, which is especially useful in microservices architectures where one task needs data from several services at once.

Types of web APIs by protocol and architecture

The second and most practical way to classify APIs is by the protocol or architectural style they use to move data between services. This is where most day-to-day decisions in web development actually happen. Below are the styles worth knowing in 2026.

1. REST APIs (Representational State Transfer)

REST is the most widely used style for building web and mobile back ends. It treats each piece of data as a resource with its own URL and uses standard HTTP methods — GET, POST, PUT, PATCH and DELETE — to act on those resources. REST is stateless, cache-friendly, and works with JSON, XML, HTML and YAML.

Its simplicity, huge ecosystem and browser friendliness make it the default choice for most public and internal web APIs. Companies like Twitter/X and Expedia have long relied on REST for their public APIs.

Best for: general-purpose web and mobile APIs, public and partner endpoints, and any service where broad compatibility matters more than raw speed.

2. SOAP APIs (Simple Object Access Protocol)

SOAP is an older, highly structured protocol that exchanges XML messages and enforces strict standards for security and reliability. It works well in decentralised, distributed environments and ships with built-in features for security (WS-Security), transactions and formal contracts (WSDL).

Because of that rigour, SOAP still appears in banking, payment gateways, CRM and telecom systems where guaranteed delivery and formal contracts matter. PayPal and Salesforce have historically exposed SOAP APIs alongside REST.

Best for: enterprise systems with strict security, compliance and reliability requirements.

3. GraphQL APIs

GraphQL is a query language for APIs that lets the client ask for exactly the data it needs — no more, no less — from a single endpoint. This solves the over-fetching and under-fetching problems common with REST, where an endpoint returns a fixed shape whether you need all of it or not.

Adoption has grown sharply: GraphQL is now common in production at large organisations, especially for mobile and front-end-heavy applications where minimising payload size and round trips matters. It is frequently used as a backend-for-frontend (BFF) layer in front of other services.

Best for: mobile apps, complex front ends, and clients that need flexible, efficient data fetching from many sources.

4. gRPC APIs

gRPC is a high-performance framework that sends binary messages using Protocol Buffers (protobuf) over HTTP/2. Compared with REST and JSON, it produces much smaller payloads and lower latency, and it supports streaming in both directions.

Those gains come with trade-offs: gRPC is harder to call directly from a browser and less human-readable than JSON, so it is used mostly for communication between internal services rather than for public APIs.

Best for: internal microservice-to-microservice communication where speed and efficiency are the priority.

5. WebSocket APIs

WebSocket provides a persistent, full-duplex connection over a single TCP connection, so the server and client can push data to each other at any time. Unlike the request-response model of HTTP, the connection stays open, which makes real-time features possible without constant polling.

Best for: chat, live notifications, collaborative editing, dashboards, multiplayer features and anything that needs low-latency, bidirectional updates.

6. Webhook APIs

A webhook flips the usual model around: instead of your app repeatedly asking “has anything changed?”, the provider sends an HTTP POST to a URL you register the moment an event happens. It is an event-driven, push-based pattern rather than a style you query on demand.

Best for: reacting to events from third-party services — payment confirmations, CI/CD triggers, form submissions, or Git push notifications.

7. RPC APIs (Remote Procedure Call)

RPC is the simplest style conceptually: the client calls a function that runs on a remote server and gets the result back, as if it were a local call. Classic RPC uses formats such as XML-RPC and JSON-RPC; gRPC (above) is the modern, high-performance evolution of the same idea.

Best for: action-oriented APIs where you are invoking commands or procedures rather than manipulating resources.

REST vs SOAP vs GraphQL vs gRPC vs WebSocket

Here is a quick comparison of the main protocol styles to help you choose.

Types of APIs by use case

The third way to classify APIs is by the system they are designed to work with.

1. Database APIs — enable communication between an application and a database management system. Developers use them to write queries, read and modify data, and manage tables. For example, the Drupal database API abstracts queries across MySQL, PostgreSQL, Oracle and others.
2. Operating system APIs — define how applications use the resources and services of an OS. Every operating system has its own set, such as the Windows API or the Linux system-call interface, and Apple’s Cocoa and Cocoa Touch for macOS and iOS.
3. Remote APIs — define how applications running on different machines interact over a network. Because the two ends are connected over the internet, most remote APIs are built on web standards.
4. Web APIs — the most common class. They transfer machine-readable data and functionality between web-based systems over HTTP, and let developers extend an app with third-party features — for example adding a map with the Google Maps API.

How do you choose the right API type for your project?

There is rarely one “correct” API for a whole system — most modern platforms mix several. A common pattern is REST for public and partner endpoints, gRPC between internal microservices for speed, GraphQL as a flexible layer for mobile and web front ends, and WebSocket for real-time features. To decide, weigh a few factors:

• Audience — a public API leans REST for broad compatibility; an internal service can use gRPC.
• Performance — gRPC wins for high-throughput internal calls; REST is fine for most external traffic.
• Data flexibility — if clients need many different shapes of data, GraphQL reduces round trips.
• Real-time needs — if updates must be pushed instantly, reach for WebSocket or webhooks.
• Security and compliance — heavily regulated systems may still justify SOAP.

Picking the API that will last is one of the harder calls in web development, and it is worth getting right early. If you want experienced help designing or building your API layer, you can hire vetted API developers through Codersera to extend your engineering team.

FAQ

What is an API in web development?

An API (application programming interface) is a defined contract that lets two software systems exchange data and functionality. In web development it usually means a set of HTTP endpoints that let a front end, mobile app or third-party service request data from, or send data to, a server in a predictable format such as JSON.

What are the main types of APIs?

APIs are classified three ways: by access policy (open, partner, internal, composite), by protocol or architecture (REST, SOAP, GraphQL, gRPC, WebSocket, webhook, RPC), and by use case (database, operating system, remote, web). Most projects care most about the protocol axis, where REST is the common default.

What is the difference between REST and SOAP?

REST is a flexible, resource-based architectural style that works with multiple formats (usually JSON) over HTTP and is easy to adopt. SOAP is a stricter XML-only protocol with built-in security and formal contracts, favoured in enterprise and high-compliance systems. REST suits most web APIs; SOAP suits regulated, reliability-critical integrations.

Is REST or GraphQL better?

Neither is universally better — they solve different problems. REST is simpler, cache-friendly and ideal for public APIs with predictable responses. GraphQL lets clients request exactly the fields they need from one endpoint, which reduces over-fetching for mobile and complex front ends. Many teams use both together.

What is the most common type of API?

REST web APIs are by far the most common in modern web development. Their simplicity, HTTP-native design, wide tooling support and browser friendliness make them the default choice for public, partner and internal services alike, even as GraphQL and gRPC grow for specialised use cases.

Is an API a web service?

Every web service is an API, but not every API is a web service. A web service is specifically an API that communicates over a network using web protocols such as HTTP (for example REST or SOAP). APIs also exist for databases, operating systems and local libraries that never touch a network.