What is an API and REST API? A Practical Guide for Developers
But what exactly is an API, and how does it differ from a REST API? These terms are often used interchangeably, but there's an important distinction that every modern developer should understand.
In this post, you'll learn everything about the API and REST API domain—from core concepts and key differences to the fascinating history of how REST and JSON became the web's integration standard. We'll explore why REST APIs dominate today's development landscape, compare different backend service models, and finally show you how to build your own APIs in practice using Codehooks.io.
What is an API?
API stands for Application Programming Interface.
Think of an API as a messenger that allows two different applications to communicate. For example:
- A payment API (like Stripe or PayPal) processes transactions.
- A maps API (like Google Maps) provides geolocation and routing data.
- A messaging API (like Twilio) sends SMS or WhatsApp messages.
APIs hide complexity and give developers clean, documented entry points. Instead of dealing with internal systems directly, you simply make calls to the API and get back data or results.
What is a REST API?
A REST API is a specific type of API based on the REST (Representational State Transfer) architectural style.
Key REST principles:
- Stateless: Each request is independent; no stored session state on the server.
- Resource-oriented: Data is modeled as resources, usually exposed via URLs.
- HTTP verbs: Use standard methods like
GET,POST,PUT, andDELETE. - Standardized responses: Typically JSON over HTTP.
REST APIs have become the default standard for web services because they’re simple, scalable, and work well across different platforms and devices.
API vs REST API: What’s the Difference?
Not all APIs are REST APIs. “API” is the general term, while REST is one style of API.
Here’s a quick comparison:
| Feature | API (general) | REST API |
|---|---|---|
| Definition | A way for software to interact | API based on REST principles |
| Protocols | Any (HTTP, gRPC, SOAP, etc.) | HTTP (with verbs like GET/POST) |
| Data format | Any (XML, JSON, binary, etc.) | Usually JSON (sometimes XML) |
| Example | SOAP API, GraphQL API, SDK function | GitHub REST API, Twitter REST API |
So when someone says “API and REST API,” they’re usually asking about the general concept vs the most common implementation.
Why REST APIs Matter for Developers
Developers love REST APIs because they’re:
- Easy to use: No special tooling required, just HTTP requests.
- Interoperable: Works across languages, platforms, and devices.
- Well-documented: Most modern APIs publish REST endpoints and examples.
- Flexible: Great for microservices, integrations, and mobile/web apps.
That’s why REST APIs are everywhere—from social media and e-commerce to finance and IoT.
Why REST and JSON Dominate the Integration Landscape
Over the past decade, REST combined with JSON has become the default way for applications, platforms, and services to integrate. There are several reasons for this dominance:
- Ubiquity of HTTP: REST leverages the existing web infrastructure. Every language, framework, and platform can make HTTP requests without special libraries or protocols.
- Lightweight data format: JSON is human-readable, compact, and easy to parse. Unlike XML, it doesn't require heavy markup, and most modern languages have built-in JSON support.
- Developer experience: JSON maps naturally to data structures in JavaScript, Python, Java, Go, and many others. This makes it faster to prototype and reduces the risk of errors.
- Performance and scalability: JSON over HTTP is efficient enough for web-scale applications, while being simpler to cache, debug, and distribute.
- Ecosystem adoption: Nearly all major APIs—from Twitter and GitHub to AWS and Google—offer REST+JSON endpoints. This sets a standard expectation for developers.
- Interoperability: REST and JSON work well across web, mobile, IoT, and backend systems. A single API can serve many clients with minimal effort.
In short, REST and JSON became the industry standard because they hit the sweet spot: simple, universal, and good enough for most integration scenarios.
A Brief History: SOAP → REST → GraphQL
To understand REST’s dominance, it helps to see where it came from:
- SOAP (Simple Object Access Protocol): Popular in the early 2000s. XML-based, strict, and very verbose. Great for enterprise but heavy and complex.
- REST (Representational State Transfer): Emerged as a lighter alternative. Uses simple HTTP methods and resource-based URLs. Easy to adopt, scales with the web, and fits developer workflows.
- JSON as the data format: Around the same time, JSON rose as the natural fit for JavaScript-heavy web development. REST+JSON became the new norm.
- GraphQL (2015+): Introduced by Facebook, GraphQL gives clients more flexibility in querying data. It's powerful but requires more tooling and isn't as widely adopted outside certain use cases.
Despite newer entrants like GraphQL or gRPC, REST and JSON remain dominant because they're simple, universal, and "good enough" for most integrations.
As REST APIs became the standard for integration, developers needed better ways to build and host them. This led to the rise of specialized cloud services that handle the heavy lifting of API development and deployment.
Let's look at how different backend service models support API development, and what that means for your tech stack choices.
BaaS vs DBaaS: How They Differ in API Support
When choosing where to build your APIs, you’ll often encounter Backend-as-a-Service (BaaS) and Database-as-a-Service (DBaaS) platforms. Both help you move faster, but they differ in what they provide out of the box.
| Category | Popular Examples | What You Get | API Support |
|---|---|---|---|
| BaaS (Backend-as-a-Service) | Firebase, Supabase, Codehooks.io | Full backend services: auth, database, serverless functions, hosting, queues, workflows | Rich API support, often automatic REST/GraphQL endpoints for data + custom logic APIs |
| DBaaS (Database-as-a-Service) | MongoDB Atlas, AWS DynamoDB, PlanetScale | Managed database only: scaling, replication, backups | APIs are database-centric; usually SDKs or query APIs, REST/GraphQL APIs must be built separately |
Key Differences:
- BaaS: Gives you batteries-included development. You store data and instantly get REST or GraphQL APIs to interact with it, often with integrated auth, security, and triggers. Perfect for rapid app development.
- DBaaS: Focuses only on providing a managed database. You still need to build and expose your own API layer using frameworks or services. Better if you want total control but slower for prototyping.
For most developers looking to build modern apps quickly, BaaS solutions with strong API support are the better starting point.
Building REST APIs with Codehooks.io
Traditionally, building a REST API means:
- Setting up a server
- Configuring a database
- Writing boilerplate code
- Handling authentication and scaling
With Codehooks.io, you can skip all that.
Codehooks.io gives you:
- Instant CRUD REST APIs backed by a serverless NoSQL datastore
- Serverless functions for custom business logic
- Authentication, queues, cron jobs, and workflows out of the box
Here’s how you can create a REST API in seconds:
import { app } from 'codehooks-js';
// Use Crudlify to create a CRUD REST API for any database collection
app.crudlify();
export default app.init();
Deploy it, and you instantly have endpoints like:
GET /api/todos→ list todosPOST /api/todos→ create a new todoPUT /api/todos/:id→ update a todoDELETE /api/todos/:id→ delete a todo
👉 That’s a fully functional REST API without servers, frameworks, or database setup.
FAQ: API and REST API
Q: What is an API in simple terms? A: An API is a way for software applications to talk to each other.
Q: What is a REST API? A: A REST API is an API that follows REST principles, using HTTP methods to manage resources.
Q: Why do REST and JSON dominate integrations? A: Because they are simple, universal, and supported across all platforms. REST leverages HTTP, while JSON is lightweight and easy to use. Together, they became the default integration standard.
Q: How did REST evolve compared to SOAP and GraphQL? A: SOAP came first—heavy and XML-based. REST+JSON simplified everything and became the web’s standard. GraphQL is powerful but more complex, so REST still dominates overall.
Q: How do I build a REST API quickly? A: Use a platform like Codehooks.io to create and deploy APIs in minutes.
Q: What’s the difference between BaaS and DBaaS? A: BaaS gives you a complete backend (database + APIs + auth + functions). DBaaS only gives you a managed database—you still need to build your own API.
Conclusion
- API = general concept (how apps talk to each other).
- REST API = the most common type, built on REST principles.
- REST + JSON = the winning combo for integrations: simple, universal, and efficient.
- History: REST+JSON displaced SOAP and still dominates despite GraphQL/gRPC alternatives.
- BaaS vs DBaaS: choose BaaS for rapid API development, DBaaS if you want database-only control.
- For developers, REST APIs are the backbone of modern apps and integrations.
If you want to experiment, prototype, or launch production-ready REST APIs fast, try Codehooks.io. You can deploy your first REST API in minutes—without servers, frameworks, or endless configuration.