API Requests Explained: Methods, Formats, and Examples

TL;DR

An API request is a message a client sends to an API server to retrieve data or perform an action. It typically includes an endpoint, an HTTP method, headers, parameters, and sometimes a body. The server returns a response containing a status code, headers, and data. To send your first request, start with a documented public API and a simple GET call.

What Is an API Request?

An application programming interface request—often called an API call—is a structured message sent from one software system to another. It tells the receiving system what data or action the sender needs.

In practical terms:

• The client asks for something.
• The API server evaluates the request.
• The server returns a response indicating success or failure.

Suppose a travel app needs to display the current weather in Hanoi. Instead of creating forecasting infrastructure, the app can request conditions from a weather service. The service responds with data such as temperature, humidity, and precipitation.

API requests power many common interactions, including:

• Signing in with an existing account
• Sending an in-app message
• Processing a payment
• Loading conversation history
• Translating text
• Retrieving product availability

Users rarely see these requests. For developers, however, understanding what was sent and returned is essential for integrating services and diagnosing errors.

How an API Request Works

Although APIs use different protocols, REST APIs are a useful starting point because they commonly communicate over HTTP or HTTPS.

Client application → API request → Server
Server → processing and validation → API response → Client application

A REST API request commonly contains the following parts.

Endpoint URL

The endpoint identifies the resource the client wants to access:

https://api.example.com/v1/cities/hanoi/weather

The base URL identifies the API, while the path points to a specific version and resource.

HTTP method

The method indicates what the client wants the server to do. A GET request retrieves information, while a POST request commonly submits information.

The endpoint and method work together. GET /messages and POST /messages can represent listing messages and creating one.

Headers

Headers provide request metadata. They can specify the expected format or carry authentication credentials.

Common examples include:

• Authorization: Bearer <token>
• Content-Type: application/json
• Accept: application/json

Do not place private server-side credentials in exposed client code.

Path and query parameters

A path parameter identifies a resource:

/users/123

A query parameter filters, sorts, paginates, or modifies results:

/messages?limit=20&before=1700000000

Documentation should identify required parameters and accepted formats.

Request body

Requests that create or update data frequently include a body. JSON is common:

{"text":"Hello","recipient":"user-42"}

Missing fields, invalid types, or malformed JSON can cause the server to reject the request.

API response

A response usually contains an HTTP status code, headers, and an optional body. Typical status codes include:

• 200 OK: The request succeeded.
• 201 Created: A resource was created.
• 400 Bad Request: The request is invalid.
• 401 Unauthorized: Authentication is missing or invalid.
• 403 Forbidden: The caller lacks permission.
• 404 Not Found: The resource does not exist.
• 429 Too Many Requests: A rate limit was exceeded.
• 500 Internal Server Error: The server encountered a problem.

The status code provides the first clue, while the response body often contains an actionable error message.

Common Types of API Requests

“API request types” can refer to the protocol or the action represented by an HTTP method.

REST requests

REST APIs organize operations around resources and generally use HTTP methods, URLs, headers, and request bodies.

Common REST API request methods include:

• GET: Retrieve a resource or collection.
• POST: Create a resource or trigger an operation.
• PUT: Replace an existing resource.
• PATCH: Update selected fields.
• DELETE: Remove a resource.

Behavior depends on the API contract. A provider may use POST for an operation that does not create a conventional resource.

RPC requests

Remote procedure call APIs are organized around named operations. A request specifies a method, parameters, and supporting metadata.

An operation might resemble sendMessage(recipient, text) rather than POST /messages. RPC systems may use JSON, XML, Protocol Buffers, HTTP, TCP, or another transport.

GraphQL requests

GraphQL clients send a query describing the exact fields they need, potentially reducing over-fetching.

Most GraphQL operations use one endpoint. The body contains a query or mutation plus optional variables. Developers must understand the schema, field relationships, and query cost controls.

SOAP requests

SOAP APIs exchange structured XML messages. A request typically includes an envelope, optional headers, and a body containing the requested operation.

SOAP remains relevant in some enterprise and regulated environments because it supports formal contracts and established security specifications.

How to Send Your First API Request

Start with a public API that permits an unauthenticated GET operation, using an API client such as Postman or Insomnia.

Follow these steps:

1. Choose a documented endpoint. Check whether it requires an API key or headers.
2. Select the method. Use GET for a read-only test.
3. Enter the complete URL. Include required parameters.
4. Add headers. Set authorization and content types if required.
5. Send the request.
6. Inspect the response. Check its status code and body.
7. Change one input. Verify that you understand the endpoint’s behavior.

For example, this request asks the JSONPlaceholder test service for post 1:

GET https://jsonplaceholder.typicode.com/posts/1

A successful response returns 200 and a JSON object with fields such as userId, id, title, and body.

If it fails:

• Confirm the URL and method.
• Check required parameters and headers.
• Validate authentication credentials.
• Look for JSON syntax or type errors.
• Read the response body.
• Check for rate limiting.

For HTTP method semantics, see the MDN HTTP request methods reference.

Better Practices for Reliable API Requests

Production integrations must anticipate invalid inputs, network failures, service limits, and security risks.

Treat the documentation as the contract

Confirm the endpoint URL, method, authentication model, required fields, data types, limits, errors, and API version before implementation.

Validate requests before sending them

Validate user input and generated payloads on the client when practical, then validate them again on your server. Send only fields required by the documented contract.

Protect credentials

Keep private API keys and signing secrets on a trusted backend. Browser and mobile bundles can be inspected, making them unsafe for privileged secrets.

Use HTTPS, short-lived tokens, least-privilege permissions, and secure server-side credential storage.

Handle failures deliberately

Separate retryable failures from errors requiring a code or input change. A timeout may justify exponential backoff, while repeating a 400 request usually will not help.

Avoid retrying non-idempotent operations unless the API supports idempotency. Otherwise, payments, orders, or messages could be duplicated.

Respect limits and monitor behavior

Follow rate and payload limits. Cache safe responses, paginate large collections, and avoid polling when webhooks or real-time events are available.

Log the endpoint, method, status, latency, and a safe correlation ID. Never log passwords, access tokens, or sensitive payloads.

How to Build an App Like This with Tencent RTC

A messaging app demonstrates API requests in practice: users authenticate, send messages, load conversations, and receive delivery events. Instead of implementing storage, synchronization, offline delivery, groups, read receipts, translation, and moderation from scratch, use Tencent RTC Chat.

A typical architecture has three layers:

1. Client application: Uses @tencentcloud/chat or TUIKit to create messages, update the interface, and receive events.
2. Application backend: Authenticates users and securely generates UserSig.
3. Tencent RTC Chat: Handles conversations, routing, history, groups, offline messages, and Push integration.

Use the Tencent RTC Chat integration overview to choose the UIKit or core SDK path. For prototypes and smaller applications, the free Chat API plan includes 1,000 monthly active users, no concurrency limits, and Push.

Implement the flow in this order:

1. Create a Chat application and obtain its SDKAppID.
2. Generate UserSig securely on your backend.
3. Install and initialize the client SDK.
4. Log in with the user ID and server-issued UserSig.
5. Send a C2C or group message.
6. Subscribe to incoming-message and conversation events.
7. Add history, receipts, moderation, and Push after basic messaging works.

Initialize Tencent RTC Chat and log in:

import TencentCloudChat from "@tencentcloud/chat";

const chat = TencentCloudChat.create({
  SDKAppID: Number(process.env.NEXT_PUBLIC_CHAT_SDK_APP_ID),
});

await chat.login({
  userID: currentUser.id,
  userSig: userSigFromYourBackend,
});

Then create and send a one-to-one text message:

const message = chat.createTextMessage({
  to: "user-42",
  conversationType: TencentCloudChat.TYPES.CONV_C2C,
  payload: { text: "Your booking has been confirmed." },
});

const result = await chat.sendMessage(message);
console.log("Message sent:", result.data.message.ID);

The SDK abstracts raw network calls but follows the same principles: it identifies the operation, authenticates the caller, serializes the payload, and returns a result or error. Keep UserSig generation on your backend, validate recipient IDs, and display send failures rather than assuming every request succeeds.

Frequently Asked Questions

What is the difference between an API request and response?

The client sends a request to ask for data or an action. The server returns a response with a status code, headers, and usually data or an error payload.

What is the most common API request method?

GET is the most familiar because it retrieves data. Applications also use POST, PUT, PATCH, and DELETE, depending on the operation.

Can I send an API request without coding?

Yes. Tools such as Postman and Insomnia let you enter an endpoint, choose a method, add headers or a body, and inspect the response without building an application.