Application Programming Interface (API)

What Is an API?

An API (Application Programming Interface) is a secure and controlled interface that enables two applications to communicate. It receives requests, executes backend services, and returns results. Think of it as a standardized service window that defines request formats, endpoints, and access permissions.

In Web3, APIs bridge front-end applications, wallets, and backend blockchain nodes or exchanges. Common use cases include querying account balances, retrieving prices, submitting orders, or broadcasting transactions—all accomplished via APIs.

What Are the Uses of APIs in Web3?

In the Web3 ecosystem, APIs serve two main functions: reading data and executing actions. Data retrieval covers on-chain balances, transaction histories, smart contract events, and exchange market data. Actions include initiating on-chain transactions, signing, and placing orders.

Typical scenarios include:

• Wallets using APIs to fetch token balances for a given address and display them to users.
• Decentralized applications (dApps) monitoring contract events via APIs to update user interfaces.
• On Gate, trading bots subscribe to real-time market data through APIs and automatically place or cancel orders based on preset strategies.

By 2025, major blockchains and exchanges offer both public and restricted APIs. Public APIs allow general data queries; restricted endpoints require API keys and signatures for account-specific operations.

How Do APIs Work?

APIs typically follow a “request-response” pattern: your application sends a request in an agreed format; the server verifies permissions and parameters, executes the operation, and returns the result. For real-time updates, a persistent connection is established to continuously deliver data.

REST is an HTTP-based approach—like accessing a resource URL and receiving JSON data. Commonly, GET is used for retrieval and POST for submission. WebSocket maintains a long-lived connection for low-latency real-time streams, ideal for subscribing to market data or contract events. RPC (Remote Procedure Call) is akin to making a phone call to execute a function remotely; blockchains often use JSON-RPC to interact with node methods.

Examples:

• Reading data: Request the “eth_getBalance” method from a blockchain node to get an address’s balance.
• Executing actions: Send a “create order” request to an exchange’s API; after signature verification, the server processes and returns the order status.

What Types of APIs Exist?

APIs commonly fall into three categories: REST, WebSocket, and RPC. REST focuses on “resource retrieval and submission,” making it simple to use and cache. WebSocket is designed for “low-latency real-time streaming.” RPC is frequently used by blockchain nodes, where you call specific functions by name.

Choose based on your requirements: use REST for periodic price polling; WebSocket for millisecond-level updates of market data and order books; RPC for direct interactions with blockchain nodes (such as Ethereum’s eth_call or eth_sendRawTransaction).

How Do You Get Started With APIs?

To begin using APIs, follow these step-by-step guidelines:

Step 1: Define your goal. Are you “reading data” or “executing actions”? For example, monitoring market prices versus automating trading and risk controls.

Step 2: Select the appropriate API—decide between an exchange’s REST/WebSocket API or a blockchain node’s JSON-RPC API; choose between official or third-party node services.

Step 3: Review documentation and rate limits. Examine endpoint paths, parameters, response formats, authentication methods, and rate limits. Assess whether you need queuing or caching solutions.

Step 4: Prepare authentication. Generate API keys, understand the signature algorithm (commonly HMAC), set up IP whitelists and minimal permissions to prevent leaks.

Step 5: Initiate requests and parse responses. Test with curl or Postman; in your code, handle errors, retries, and timeouts; parse JSON responses and validate fields.

Step 6: Deploy and monitor. After launch, log activity, monitor latency, disconnects, and failure rates; set up alerts and backup plans.

What Can You Do With APIs on Gate?

On Gate, APIs allow you to access market data, order book snapshots, account balances; execute orders, cancel trades, check order status; and subscribe to real-time trade feeds to power automated strategies.

Example 1 (REST for spot market data):

curl -s https://api.Gate.com.ws/api/v4/spot/tickers?currency_pair=BTC_USDT

This request returns the latest price and volume data for BTC_USDT. Refer to Gate’s developer documentation for parameter details and response fields.

Example 2 (WebSocket subscription for trade feed):

# Example only—refer to Gate documentation for actual channels and authentication
wss://api.Gate.com.ws/ws/v4/
# Send subscription message
{"time":1730000000,"channel":"spot.trades","event":"subscribe","payload":["BTC_USDT"]}

Example 3 (general flow for placing orders via restricted endpoints): First generate an API key in your dashboard; create a signature and necessary headers according to documentation; then POST to the order endpoint and verify returned order ID and status. Always consult the latest Gate docs for specifics.

What Is the Difference Between API and RPC?

API is a general term for any externally callable interface; RPC is a specific implementation emphasizing “calling remote functions as if they were local.”

In blockchain systems, JSON-RPC is the most common node interface. The difference lies in interaction style:

• REST is resource-centric, using paths and HTTP verbs.
• RPC is method-centric, using “method + params.”
• Both are types of APIs—the choice depends on your use case and tooling.

For example: To query ETH balance use the RPC method “eth_getBalance”; for exchange price info use the REST path “/spot/tickers”.

What Are the Risks of Using APIs?

When APIs involve accounts or assets, main risks include key leakage, operational errors, and system stability issues. If your key is compromised, attackers can perform authorized operations; incorrect parameters may trigger unintended trades; network instability affects real-time strategies.

To mitigate risks:

• Avoid hardcoding API keys in code repositories; use environment variables or key management systems.
• Enable IP whitelisting and minimal permission—grant only necessary endpoints.
• Add risk controls and secondary confirmation for critical operations like order placement.
• Implement retry with backoff strategies; set timeouts and auto-reconnect logic.
• Regularly audit logs to spot suspicious requests and promptly revoke compromised keys.

Asset-related actions carry loss risk—use APIs cautiously according to your technical capability and compliance requirements.

What Are the Future Trends of APIs?

As of December 2025, three key trends are shaping Web3 APIs: first is real-time low-latency connectivity—with WebSocket and streaming interfaces becoming mainstream; second is increased security and regulatory compliance—fine-grained key permissions and advanced signature schemes are continuously enhanced; third is higher data abstraction—with more services providing aggregation and indexing layers that reduce direct complexity when interacting with nodes.

Developers increasingly rely on SDKs and hosted node services that combine REST, WebSocket, and JSON-RPC to build unified systems capable of both reading data and executing transactions.

What Are Some Resources to Learn About APIs?

Start learning about APIs with official documentation and sample code, then move on to hands-on practice and monitoring.

Recommended steps:

• Read the relevant platform’s API docs (for Gate: review REST/WebSocket authentication guides).
• Validate requests/responses using curl or Postman.
• In code implementations, add error handling, rate limiting, and caching.
• After deployment, observe logs and metrics to optimize stability and latency.

In summary: mastering APIs means understanding how applications connect with blockchains and markets. Grasp the types and principles, follow platform documentation when coding or managing risk controls, so you can reliably integrate Web3 data and capabilities into your products.

FAQ

What Is the Difference Between REST API and WebSocket API?

REST API uses a request-response model where each query requires you to send a new request; WebSocket API establishes a persistent connection allowing servers to push updates proactively. REST suits low-frequency queries; WebSocket is ideal for scenarios requiring real-time data streams such as live trade feeds.

How Should I Choose the Right API for Trading Integration?

Consider three factors when selecting an API: feature coverage (support for required trading types), stability/speed (API response latency), and quality of documentation/support. Gate provides comprehensive trading API docs and technical support—new users can start testing in a sandbox environment.

What Does Rate Limiting Mean When Calling an API?

Rate limiting refers to rules set by API providers that restrict how many requests you can make within a certain time frame to maintain system stability. Exceeding limits results in temporary denial of service. Limits vary by API tier—always check official docs for specifics and plan requests to avoid throttling.

What Should I Do if My API Key Is Leaked?

API key leaks pose asset risks—immediately regenerate your keys if exposed. Go to your platform’s API management page; delete compromised keys and create new ones (old keys are instantly invalidated). Regularly rotate keys, enable IP whitelisting for access control, and never hardcode sensitive keys in your codebase.

Why Do My API Requests Keep Returning Error Codes?

Common causes of API errors include signature validation failures (check timestamps/encryption), incorrect parameter formats (follow documentation), missing required headers in requests, or network issues. Debug by testing with Postman or similar tools; review error messages then cross-check with API docs to resolve issues step by step.