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What Is a Web3 API and Why Does It Matter?

Blockchains are, at their core, self-contained databases. When building Web3 apps, you need a way to query that database for existing data and a way to write new data to it. This is where Web3 APIs come in.

Deep dive
February 1, 2023
Developer Advocate
Web3 APIs

A Web3 API helps you connect your dApp (decentralized application) to a blockchain and integrate with other services in the ecosystem. Read on to learn more about why Web3 APIs matter and what you can do with them. 

What Is a Web3 API?

A Web3 API (application programming interface) is a set of standards that enable decentralized applications (dApps) to access and index all the blockchain information they need, broadcast new transactions, and scale to meet demand. 

Traditionally, APIs are solutions that allow different software programs to communicate with each other. The same is true for a Web3 API, but rather than enable communication between two different applications, a Web3 API enables communication between an app and the blockchain.

API Endpoints and How to Interact with Them

An API sets the standard for how two applications can communicate, and API endpoints help you interact with the API in a predictable and consistent way. An API endpoint is a specific URL that is associated with a certain action or set of operations. For example, you may interact with a dedicated endpoint to query NFT holdings for a particular address and a different endpoint to query pending transactions in the blockchain mempool.

How you interact with a particular endpoint depends on which API protocol you are interacting with. For a REST API, you send a simple HTTP request to a particular endpoint to retrieve data or to broadcast a transaction. For a SOAP API, you will use an XML data format to retrieve and post data.

Types of API Protocols

There are many types of API protocols out there, and you may encounter several of them when exploring Web3 API options. Types of API protocols include:

  • Representational State Transfer (REST): this is the most common API protocol in Web2 and Web3. REST APIs are stateless, can cache responses, and have a client-server architecture (the user interface is separated from the backend). This makes REST APIs fast, flexible and light: in other words, they offer great performance, which makes them popular for developers today.
  • Remote Procedure Call (RPC): this messaging standard is older than REST and the fundamental difference between the two is that RPC is designed around calling actions in a separate network, like a blockchain, while REST is designed around resources. Blockchain RPCs are usually simple and limited, and other APIs are preferred for handling large quantities of data.
  • Simple Object Access Protocol (SOAP): SOAP is a legacy API protocol defined by the World Wide Web Consortium and one that is still popular today. SOAP uses the RPC protocol but is itself a standard of its own and offers a more rigid structure and datatype control (compared to a REST API) that in turn offers stronger security benefits.
  • WebSocket: unlike REST, WebSocket APIs are both stateful and bi-directional. They support real time communication between applications. Since WebSocket enables communication to flow both ways between the client and server at the same time, WebSockets are useful for apps that need to transmit a high volume of messages back and forth.
  • GraphQL: this isn’t an API protocol per se, but a query language that you can use on top of an API to query API data. GraphQL pulls all of your API’s data into a singular endpoint, and you can use a query language to request data that GraphQL has organized by type and field.

What Can You Do with a Web3 API

APIs are important components of the digital economy. In a 2021 Developer Survey, “90.5% of developers expect to use APIs more or the same” in 2022, and 75.5% of developers say that their organizations are already prioritizing or planning to prioritize leveraging APIs in the near future.

So it’s not surprising that Web3 APIs have become a key component of the tech stack for Web3 developers. A Web3 API is the key to querying all kinds of blockchain data. Without a Web3 API, your app won’t be able to access the data stored on the blockchain on which it is built, and if that’s the case, then you aren’t building on a blockchain at all.

Let’s take a closer look at the information you can query via a Web3 API. This list isn’t exhaustive, but will give you an idea of how important Web3 APIs can be for various kinds of applications.

Transactional Data 

You can fetch transactional data for use in your Web3 apps through transaction endpoints. These endpoints allow you to query that data by wallet address, by transaction ID, by block, and more.

Account Data

With an accounts endpoint, you can request a record of transactions from a specific account address, get the native balance of that account, and more.

Block Data

Retrieve information on past and current blocks via various block endpoints. You can query the mempool (pending transactions), pull recent blocks, get a particular block height and more. These endpoints can help you verify the integrity of the chain and build historical data on block development over time.

Smart Contract Data 

Through smart contract endpoints, you can query contract info, pull a list of events triggered by a particular contract, call a contract’s read-only function, and more. This is helpful for monitoring analytics around any smart contracts in your application and interacting with other apps in the ecosystem.

Token Metadata

If you need to display token metadata in your app, you can pull that information into your app via a token endpoint. This is particularly useful for decentralized finance (DeFi) applications that need to display information, such as a token name, its logo, total supply, its price, and more.

NFT Metadata

NFTs have emerged as a key pillar of Web3, and through NFT endpoints, you can fetch data and metadata relating to them, such as its specific image graphic, token collection name, the USD-denominated price of its last trade, ownership data, transfer history, and more.

Why Do Web3 APIs Matter?

Web3 APIs are crucial for pulling ecosystem data into applications and for those applications to broadcast new data to the blockchain. API providers provide lightweight, low-latency, easily searchable indexes of blockchain data that can be queried live by your application to provide relevant information to your users. Without a Web3 API, you wouldn’t be able to query the account balance of your user and determine whether they have the funds necessary to buy an item in your app, nor would your app have a way to broadcast that purchase so it got picked up and recorded in a blockchain. 

Which Are the Most Popular Web3 API Providers?

Web3 developers can forego using a Web3 API provider by spinning up their own blockchain node and leverage the protocol’s native API on their own to query, index, and serve relevant data to their dApp users, but this can be extremely time-consuming, expensive, and provide fewer guarantees of uptime.

They could also simply leverage existing third-party API services instead. Because APIs are critical infrastructure, many companies across different blockchains offer APIs as a service to provide a reliable and scalable experience to builders within their ecosystem(s).

Running Your Own Node

Running a blockchain node has some advantages, such as giving you control of the kinds of data you index for your application, as well as ensuring the validity of all data since you sourced it yourself directly from the blockchain. Also, some API service providers may charge a fee. Examples include:

Stacks Blockchain API

To access the Stacks Blockchain API, you’ll need to set up a Stacks node. You can find information on how to spin up a Stacks node here. Every running node exposes an RPC API, allowing developers to interact with the Stacks blockchain without engaging with any centralized services. Learn more about the API here.

Ethereum Blockchain API

To access the Ethereum blockchain API, you’ll start by setting up a node for Ethereum, just like you would for Stacks. You can learn more about setting up an Ethereum node here. Every node comes with an implementation of a JSON-RPC API, which allows you to interact with the Ethereum blockchain. Learn more about the JSON-RPC API here.

Examples of Third-Party Web3 API Service Providers

Running a node means that you’ll incur some infrastructure costs while also expending time and other resources to keep the node operational. It takes a lot of DevOps expertise to run a reliable node that can scale to thousands, and eventually millions, of requests. For developers who do not want to take on the overhead associated with running their own node, Web3 API service providers deliver ecosystem API services without the logistical hassles for developers. If you choose to leverage a third-party service, some popular Web3 API services include:

Stacks Blockchain API

The Stacks Blockchain API is an open-source product that we created here at Hiro. It is a developer-friendly REST API capable of processing hundreds of millions of queries a month for the Stacks and Bitcoin blockchains, and we host the node and maintain the infrastructure. Learn more about how we scaled the Stacks API here. Through the Stacks API, you have all of the functionality of using the protocol API but without the hassle of running your own node and dealing with reliability and scalability. We handle that hassle for you.

Learn more about Stacks API here.

Alchemy API Service

Alchemy offers many developer tools (among them an API) for developers to build with several EVM and non-EVM chains, including Ethereum, Ethereum L2s, and Solana. Alchemy’s API is broken into a series of microservice APIs (dedicated APIs for NFTs, transfers, etc) for better performance. You can access Alchemy’s APIs via POST requests or WebSocket, and it’s designed to be highly available and reliable, with low latency and high uptime.

Learn more about Alchemy here.

Infura Ethereum API

Infura’s API service enables developers to build dApps that can interact with a variety of chains (including Ethereum, NEAR, and IFPS) using HTTPS and WebSockets. It’s the oldest service provider on Ethereum (it’s been live since 2016), and you can connect to the Ethereum network with just a single line of code. Like any service, Infura is designed to offer reliable uptime, instant accessibility, and adjustable limits.

Learn more about Infura here.

Moralis Web3 API

Moralis also provides Web3 developers with a suite of different API references for use on several supported chains, including Ethereum, Binance, Solana. Moralis is the newest entrant to the space (apart from us at Hiro) and launched in 2021 with a focus on cross-chain support. Like Alchemy, Moralis breaks its API into microservices (such as a block API and a transaction API).

Learn more about Moralis here.

Kickstart Your Development Journey into Web3

Web3 APIs are a critical part of the Web3 tech stack. Now that you have a sense of how to use a Web3 API, check out our free guide to developing smart contracts to learn more about the Web3 tech stack and how you can create your own dApp.

Download Hiro’s Guide to Developing Smart Contracts
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