RPC vs. API: What’s The Difference?

Published in

Ankr

5 min readApr 7, 2022

Introduction

If you’re new to the world of Web3 development, you may have heard the terms “RPC” and “API” floating around and wondered what they mean. This article will explain exactly what these terms mean, how they’re related, and how they’re different. And you’ll get a good sense of where these concepts fit into the Web3 development landscape. Let’s dive in!

RPC vs. API

First up, let’s break down “RPC.” RPC stands for Remote Procedure Call. This is a type of protocol that enables one computer or program to remotely communicate with another computer or program. In the simplest terms, RPCs enable you to connect to a network.

An RPC must be initiated by the client (or requester), which sends a message (or a request) to a remote server (or receiver). Once the server receives the request, it sends a response to the client, and the client continues with the process it was originally running.

Next we have “API.” API stands for Application Programming Interface. This enables one computer or program to interact with other computers or programs over a shared network. Once you’ve connected to a network, APIs are what enable you to communicate with other devices on that network.

Although you may have heard these terms used interchangeably, RPCs and APIs are two distinct things. APIs essentially represent the framework that enables remote computers in a shared network to communicate with one another, whereas the RPCs (or calls) are the means by which they communicate. In other words, the calls represent the communication itself, but an API defines these calls, functionally explaining how to use them in that particular network.

Perhaps the clearest distinction between RPCs and APIs is this: RPCs connect you to a network; APIs let you communicate with other devices on a network.

An Example of RPCs and APIs

The nuance between RPCs and APIs is perhaps best illustrated by an example, which we’ll take a look at now. Remember that RPCs are responsible for connecting to a network, and APIs are responsible for interacting with other computers or programs on that network. It boils down to the fact that the RPC is local, whereas the API is communicative.

Let’s look at one more example. Imagine you emailed your mom asking her to make some cookies for you. This is essentially an RPC. You (the client) provide your mom (the server) with a request for cookies. Your mom does some baking behind the scenes, and sends you the cookies, completing your request.

But let’s say you now decide you want a pizza, and mom is fresh out of ingredients, so you go to a pizzeria instead. Unlike at mom’s house, you can’t just go into the kitchen and start using their ingredients. You have to go up to the counter and place an order — and there’s a menu that lists what pizzas you can order, and what toppings or other options you can pick. This is an API.

An RPC is a specific request, but an API is a framework for communication.

RPCs and APIs in Web3

So where do RPCs and APIs fit into Web3 development? Well, Web3 developers need to communicate with blockchain networks. Blockchain communication relies on network nodes. And if a developer doesn’t want to go through the hassle of setting up and operating their own nodes, they can opt to remotely connect to existing blockchain nodes via these tools.

The relationship between RPCs and APIs in a Web3 context is the same as their relationship in a Web2 context, only with different infrastructure. That means RPCs will help you to connect to a blockchain network; APIs will enable you to interact with other nodes in the network. Now let’s break that down a bit more.

RPCs help Web3 developers communicate with remote blockchain nodes via data requests. Web3 wallets, for example, can rely on an RPC endpoint to request data from blockchain nodes.

These requests might look something like ‘how many X tokens are in Y wallet?’, or ‘does this user have enough X tokens to cover the gas fee for this transaction?’ To get the answer to those questions, you can use RPCs to query the blockchain for the data you need.

On the other hand, if you want to read and write data to the blockchain, you’ll need to use a full-fledged API that enables two-way communication between nodes in the network. If, for example, you’re using a decentralized exchange (DEX) to swap one token in your wallet for another, you’ll need to write data to the blockchain with your updated wallet balance. Similarly, if you’re building a dApp that’s constantly interacting with blockchain networks (not just requesting data), then you’ll need to use an API.

Ankr’s RPCs and APIs

So where does Ankr fit into all of this? To use our example from earlier about cookies and pizza, Ankr provides the resources to build the restaurant. Ankr offers connectivity to a globally distributed, decentralized network of independent node providers via Ankr Protocol. You can connect to Ankr Protocol via RPC or API.

Ankr Protocol offers free, public RPC endpoints to users directly from https://www.ankr.com/protocol/public/. Simply copy and paste the RPC endpoint into your Web3 wallet to start sending RPCs through Ankr’s fast, decentralized node infrastructure. Ankr’s free RPC endpoints connect to nodes in the US and EU. These free RPC endpoints are especially useful for users looking to expand the default functionality of MetaMask to support other blockchain networks and cryptocurrencies. Simply plug these RPC endpoints into your MetaMask wallet and manage multiple types of assets from one convenient location.

For users, developers, and protocols looking for API connectivity to power their projects, Ankr Protocol offers a Premium Plan that includes private endpoints, WebSockets (WSS) capabilities, prioritized traffic, and unlimited requests with no rate limits. Ankr Protocol’s Premium Plan also affords users the ability to connect to nodes all over the world for the fastest connections and lowest latency possible. Learn more about the Ankr Protocol Premium Plan at https://www.ankr.com/protocol/plan/.

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