Every wallet and app that talks to a blockchain does it through an RPC endpoint. This article explains what that is, what the trade-offs of public endpoints are, and how to check and add one safely.
What an RPC endpoint is
RPC stands for remote procedure call. An RPC endpoint is a web address of a blockchain node that answers questions and accepts transactions. A node is a computer that holds a copy of the chain.
For example, an endpoint can answer "what is the balance of this address?", "what is the latest block?" or "what would this transaction cost?". It can also accept a signed transaction and pass it to the network. On Ethereum-style chains, the common format is JSON-RPC over HTTPS. Solana uses a similar JSON-RPC format with its own methods.
An endpoint is not the chain itself. It is a door into it. If the door is slow or wrong, what you see is slow or wrong.
How wallets and apps use it
When you open a wallet and see your balance, the wallet asks an RPC endpoint. When you press "send", the wallet signs the transaction on your device and sends the signed data to the endpoint, which forwards it to the network. Your private keys never go to the endpoint. See wallets and keys.
A wallet comes with a default endpoint for each chain. You can change it. On networks that the wallet does not know, you add one yourself, together with the chain ID, the network name and the symbol of the coin.
Public and private providers
- Public endpoints are free and open to anyone. Foundations, chains, communities and companies run them. They are good for light use.
- Private or paid providers give you your own access key, higher limits, better support and often faster, more stable service. They are used by apps with many users.
Public endpoints share capacity between all users, so they are less predictable. A paid plan gives you more control, but you pay and depend on a company. For a normal wallet user, a public endpoint is often enough. For a business app, a private one is a better fit. ChainMonitor does not recommend any provider.
Rate limits
To protect themselves, public endpoints limit how many requests you can make per second or per day. If you go over, they answer with an error such as "429 too many requests", or they slow you down. A wallet may then show an empty balance or fail to send. The cure is to wait, use another endpoint or use a private plan.
Latency and block lag
Two numbers tell you how healthy an endpoint is.
- Latency: how long a request takes to get an answer, in milliseconds. Lower is better. It depends on distance and load.
- Block lag: how many blocks the endpoint is behind the newest block of the network. An endpoint that is a few blocks behind shows older balances, can say a transaction is missing when it is not, and may give wrong fee estimates.
Why can one endpoint be behind? Its node may have lost connections, may still be syncing, or may sit behind a cache that updates slowly. If a balance in your wallet looks wrong, a lagging endpoint is one of the first things to check. You can also try the same address on a block explorer.
Privacy
An endpoint sees every request you send. That includes your IP address and the addresses you look up. The operator can link your IP to your wallet addresses. Some providers publish a privacy policy that says what they log. Others do not.
To lower the risk:
- Read the provider's tracking and logging policy.
- Use a different endpoint, or a VPN, if you do not want the operator to see your IP address.
- Remember that all transactions end up public on the chain anyway. The risk is about linking your identity to your addresses.
- Run your own node if privacy matters a lot.
How to add a custom RPC in a wallet
Details differ between wallets, but the steps are similar.
- Open the wallet's network settings and choose to add or edit a network.
- Enter the network name, the RPC URL, the chain ID, the currency symbol and, if asked, a block explorer URL.
- Save and switch to the network.
- Check that your balance loads and that the wallet shows the right network.
Take the chain ID from a trusted source. A wrong chain ID or a fake RPC address can show false data. Only add endpoints from sources you trust.
ChainMonitor's RPC health page
The chains page lists public RPC endpoints for the chains the site covers. For each endpoint, it measures:
- Latency: the time to answer a request.
- Block height: the latest block number the endpoint reports.
- Lag: how many blocks that height is behind the newest block reported by the other healthy endpoints of the chain.
The list is sorted with the fastest first, so you can see at a glance which ones are healthy. Open a chain, for example from /chains/<id>, to see its endpoints in detail. Each one has a one-click add to wallet button, which asks your wallet to add that network with the correct chain ID. You still confirm the request in your wallet. Check the values before you approve.
The numbers are measurements taken from the site's servers at a point in time. Your own latency depends on where you are. Use them as a guide, not a guarantee.
Frequently asked questions
What does RPC mean in crypto?
It means remote procedure call. An RPC endpoint is a web address that lets wallets and apps talk to a blockchain node.
Are public RPC endpoints safe?
They cannot take your funds, because signing happens in your wallet. But they can see your IP address and the addresses you query, and they can show wrong or old data. Use endpoints from sources you trust.
Why does my wallet show the wrong balance?
The endpoint may be behind the chain, rate limited or down. Switch to another endpoint and refresh. You can also check the address on an explorer.
What is block lag?
It is the number of blocks an endpoint is behind the newest block. A large lag means old data.
Do I need my own RPC provider?
Most people do not. A wallet's default endpoint is fine for normal use. If you build an app or send many requests, a private plan or your own node can be a better fit.