Mastering REST vs RESTful: Key Differences, Best Practices, and Future Trends

Overview

REST was first defined by Roy Fielding in 2000 and has become the de‑facto standard for modern web APIs. Although terms such as REST, REST‑like, and RESTful are widely used, their precise meanings are often confused.

This article examines the origins of REST and RESTful, clarifies recommended usage, and details the subtle distinctions between related terminology.

Definition and History of REST

REST (Representational State Transfer) is an architectural style composed of several constraints:

Statelessness

Client‑server separation

Layered system

Cacheability

Uniform interface

Fielding’s 2000 dissertation described REST as a "SOAP killer" and highlighted its flexibility compared with SOAP. By 2022, the vast majority of public APIs adopt REST principles.

RESTful Definition

A RESTful API follows the REST constraints but may not fully satisfy HATEOAS (Hypermedia as the Engine of Application State). Developers often label services as "REST‑based" or "REST‑ish" when they implement only a subset of the constraints.

Future of REST/RESTful

Surveys show that roughly 82 % of APIs are RESTful (using OpenAPI/Swagger), while GraphQL accounts for about 19 %. GraphQL is not a direct competitor—it is a query language rather than an architectural style. Despite hype, REST remains dominant and is unlikely to be replaced in the near term.

URI Format

A typical URI pattern is:

{base‑path}/{area}/{version}/entity1/{entity1}/{entity2}

Components:

Base path: {dns‑name}/{microservice‑name} Area (e.g., api or management)

Version (e.g., v1)

Entity names should be plural nouns; compound names use hyphens (e.g., customers‑orders).

Field Naming Rules

Use camelCase.

No spaces or underscores.

Prefer descriptive names; avoid abbreviations unless industry‑standard.

Identifiers end with Id (e.g., orderId).

Keep naming consistent across POST, PATCH, and GET.

API Response Details

Omit empty fields; treat empty strings as null.

Return empty arrays for collection fields with no items.

Use ISO‑8601 for date‑time values.

HTTP Methods and Status Codes

GET – Retrieves a resource representation; must be safe and idempotent.

POST – Creates a new resource; not safe nor idempotent.

PUT – Creates or replaces a resource; idempotent.

PATCH – Applies partial updates; not necessarily idempotent. Only the replace operation is required for simple use cases.

Common status codes:

200 OK – Successful retrieval or update.

201 Created – Resource successfully created.

400 Bad Request – Invalid client input.

401 Unauthorized – Invalid authentication token.

403 Forbidden – Authenticated but not authorized.

404 Not Found – Resource does not exist.

409 Conflict – Resource already exists or cannot be deleted due to dependencies.

503 Service Unavailable – Used to signal circuit‑breaker state.

Batch Requests

Batch creation, deletion, or update is performed via a /batch or /batch‑delete endpoint using a POST request with an array of resource objects or IDs.

[{ "name": "Raj", "taxId": 10, "mainDetail": { "number": "12345" } }, { "name": "Jack", "taxId": 10, "mainDetail": { "number": "3457" } }]

Responses contain an array of status objects, each indicating success (e.g., 200) or failure (e.g., 400).

Version Control

Major versions are encoded in the URL (e.g., /v1). Minor, patch, or non‑breaking changes follow semantic versioning. Breaking changes must trigger a new major version and be rolled back if they violate the contract.

API Error‑Handling Best Practices

Always return appropriate HTTP status codes.

Use 4xx for client‑side errors, 5xx for server‑side errors.

Include a JSON error object with code, field, message, and optional info URL.

Do not expose internal stack traces or sensitive details.

Response Body Structure

Error objects should be listed in an errors array, allowing multiple errors per request.

HTTP Headers

X‑Request‑Id

– Transaction identifier propagated across services. Content‑Type – Must be set on all responses.

Filtering, Sorting, and Pagination

Simple filtering uses query parameters (e.g., ?firstName=John). Advanced filtering supports logical operators, comparison operators, and nested field notation.

.../orders?filter=summary="Test" AND closedFlag=false

Pagination follows cursor‑based forward pagination. Clients request limit records and receive a Link header with a rel="next" URL containing the cursor of the last record.

Field Selection

Clients can request specific fields via a fields query parameter (comma‑separated). Default fields are always returned; non‑default fields are omitted unless explicitly requested.

Health‑Check and Version APIs

Health‑check endpoints expose service status and downstream dependency health without invoking other services. Version endpoints return service name, timestamp, current version, supported versions, repository URL, and build metadata.

Conclusion

Designing a robust RESTful API requires careful attention to URI design, naming conventions, HTTP method semantics, error handling, filtering, pagination, versioning, and health monitoring. Following these best practices ensures APIs are easy to use, maintainable, and future‑proof.