What Is an RPC Node? Real Requests on 4 Chains

Quick answer

What is an RPC node, in short?

An RPC node is a node that keeps a copy of a blockchain and opens a door for apps to talk to it. RPC means remote procedure call: your app asks the node to run a function and send back the result.

The door has an address, called the RPC endpoint. Apps send requests there, usually as small JSON messages over HTTPS or WebSocket.

It reads and relays. It answers questions about blocks, balances and contracts, and passes your signed transactions to the network. On most chains it does not make blocks itself.

Same software as other nodes, with the API turned on
Answers in JSON, one reply per request
Never needs your private key

CHAPTER 01

What an RPC node does, and what it does not

A node with its API switched on. Nothing more mysterious than that.

An RPC node is a full or archive node that serves an API. It stores the chain, checks every new block, and answers app requests about that data. It also forwards transactions to the rest of the network.

Every wallet and dapp needs one. When MetaMask shows your balance, it asked an RPC node. When you press send, your wallet signs the transaction on your device and an RPC node passes it on.

"RPC node" names a job, not a different kind of software. On Solana the docs say it plainly: the RPC node runs the same software as a validator, but it "does not participate in the consensus process". It spends its power on answering requests.

An RPC node next to a validator
Question	RPC node	Validator
Keeps a copy of the chain	Yes	Yes
Answers app requests	Yes, that is its job	Usually closed to apps
Makes or votes on blocks	No	Yes
Needs stake	No	On proof of stake chains
Earns rewards	No	Yes, with risk

Small or test setups sometimes do both on one machine. Solana's docs advise against it on mainnet, because the node does neither job well.

How much history an RPC node can answer about depends on the node type. A full node answers about recent state; for balances at old blocks you need an archive node. The hardware each chain needs is in the node requirements index.

CHAPTER 02

How an RPC request works, with real answers

Four steps, then five real requests you can copy.

Your app writes a small JSON message naming a method and its inputs, sends it to the endpoint, and the node looks up the answer in its copy of the chain and sends back JSON with the same id.

Step 1: Your app writes the requestA method name like `eth_blockNumber`, its inputs, and an id to match the reply.
Step 2: It goes to the endpointOver HTTPS for one question, or over a WebSocket kept open for a stream of them.
Step 3: The node looks it upIt reads its own database. No other node is asked, which is why a node that falls behind gives stale answers.
Step 4: The reply comes backEither a `result` or an `error`, never both, with the same id.

Here is what that looks like. We asked public mainnet nodes the same simple question in October 2026: how far along is the chain? Pick a chain to see the request, the exact reply, and what it means.

Real requests

One question, asked to four chains

What is the newest block?

request

curl https://YOUR-ENDPOINT \
  -H 'content-type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}'

response

{"jsonrpc":"2.0","result":"0x190fa4c","id":1}

0x190fa4c is hexadecimal for block 26,278,476. Ethereum sends every number in hex with a 0x in front, so your code converts it.

Answer from a public mainnet node, October 2026. Method reference: Ethereum JSON-RPC docs.

What is the newest slot?

request

curl https://YOUR-ENDPOINT \
  -H 'content-type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"getSlot"}'

response

{"jsonrpc":"2.0","result":461755631,"id":1}

Slot 461,755,631, as a plain number. A slot is a time window in which one block can be made, so slots and block heights are not the same count.

Answer from a public mainnet node, October 2026. Method reference: Solana RPC docs.

How many blocks does the node have?

request

curl https://YOUR-ENDPOINT \
  -H 'content-type: text/plain' \
  -d '{"jsonrpc":"1.0","id":1,"method":"getblockcount","params":[]}'

response

{"result":973262,"error":null,"id":1}

Block 973,262. Bitcoin Core answers in its older format, with "error":null, unless you ask for version 2.0. On your own node the call also needs a password.

Answer from a public mainnet node, October 2026. Method reference: Bitcoin Core RPC interface.

Is the node in sync, and what is the newest block?

request

curl https://YOUR-ENDPOINT/status

response

{"jsonrpc":"2.0","id":-1,"result":{
  "node_info":{"network":"cosmoshub-4","version":"0.38.22", ...},
  "sync_info":{
    "latest_block_height":"33590569",
    "latest_block_time":"2026-10-26T17:52:08.53650243Z",
    "catching_up":false}, ...}}

Block 33,590,569, and catching_up: false means the node is in sync. CometBFT also takes a plain web address like /status, so no request body is needed.

Answer from a public mainnet node, October 2026. Method reference: CometBFT RPC reference.

The same Ethereum question, with the method name misspelled.

request

curl https://YOUR-ENDPOINT \
  -H 'content-type: application/json' \
  -d '{"jsonrpc":"2.0","id":3,"method":"eth_blockNumbr","params":[]}'

response

{"jsonrpc":"2.0","id":3,"error":{"code":-32601,"message":"Method not found"}}

No result, an error instead. Code -32601 is the standard JSON-RPC code for a method the node does not have. The id still matches, so your app knows which request failed.

Answer from a public mainnet node, October 2026. Method reference: JSON-RPC 2.0 specification.

Notice that each chain speaks its own dialect. Ethereum sends numbers in hex. Solana counts slots. Bitcoin Core uses an older reply format by default. Cosmos takes a plain web address. Libraries like ethers.js or @solana/kit hide these details, but this is what travels under them.

1016100

CHAPTER 03

The parts of a request, a reply and an error

Four fields out, three fields back, and five error codes worth knowing.

Most chains use JSON-RPC 2.0. A request has "jsonrpc", "method", "params" and "id". A reply has "jsonrpc", "id" and either "result" or "error". The JSON-RPC 2.0 specification defines the error codes every node uses.

The fields of a JSON-RPC 2.0 request and reply
Field	In	What it holds
`jsonrpc`	Both	Always the text "2.0"
`method`	Request	The function to run, such as `eth_getBalance` or `getSlot`
`params`	Request	The inputs, as a list or an object. Some methods take none
`id`	Both	A number or text you choose. The reply carries it back. Leave it out and the node sends no reply at all
`result`	Reply	The answer, when the call worked
`error`	Reply	A code and a message, when it did not

Error codes you will meet

Standard JSON-RPC error codes and what to do
Code	Message	What went wrong	What to check
-32700	Parse error	The node could not read your JSON	A missing quote or bracket in the body
-32600	Invalid Request	Valid JSON, but not a proper request	The `jsonrpc` and `method` fields
-32601	Method not found	The node does not offer that method	Spelling, or a method your node or plan does not enable
-32602	Invalid params	The inputs are wrong	Number of inputs, hex format, address length
-32603	Internal error	The node failed while answering	Retry; if it repeats, the node needs attention
-32000 to -32099	Server error	Codes each client defines itself	The message text, which says more

Codes and messages from the JSON-RPC 2.0 specification. Rate limits are not JSON-RPC errors: a busy shared endpoint answers with HTTP status 429 before your request reaches a node.

Which block are you asking about?

Many methods take a block as an input. On Ethereum you can pass a number or a tag: latest (newest block), safe, finalized (cannot be reversed), pending or earliest (block 0), as the Ethereum JSON-RPC docs list them. Solana calls it commitment: processed is newest but can still be rolled back, confirmed has votes from more than two thirds of stake, and finalized is the default.

CHAPTER 04

HTTP, WebSocket and the ports each node uses

Ask once over HTTP, or keep a WebSocket open for live updates.

HTTP is for single questions: send, get one answer, done. WebSocket keeps a connection open so the node can push new blocks, logs or account changes to you as they happen. Each client listens on its own default port, such as 8545 for Geth over HTTP and 8546 for its WebSocket.

Use HTTP for reads and sending transactions. Use WebSocket when you would otherwise ask "anything new?" every second: a trading bot watching blocks, or a wallet waiting for a payment to land. Subscriptions like eth_subscribe or Solana's accountSubscribe only work over WebSocket.

Default RPC ports, from each client's own code or docs
Client	Chain	HTTP	WebSocket
Geth	Ethereum	8545	8546
Bitcoin Core	Bitcoin	8332	None
Solana local node	Solana	8899	8900
CometBFT	Cosmos Hub	26657	26657, path /websocket

Checked October 2026. Geth and CometBFT listen only on the machine itself (127.0.0.1) unless you change it. Bitcoin Core's port is set in its chain parameters code.

On a hosted node you never type these ports. You get a private address, and the provider routes it to the right port behind its firewall.

CHAPTER 05

Public, shared, dedicated or your own RPC node

Four ways to get an endpoint, from free to fully yours.

You can use a free public endpoint, a shared paid plan, a dedicated node someone runs for you, or a node you run yourself. They answer the same calls. They differ in limits, price, and who else uses the node.

Four ways to get an RPC endpoint
Kind	Who uses it	How you pay	Good for
Public endpoint	Anyone	Free	Trying things out and quick scripts
Shared plan	Many paying customers	Per request, in credits or units	Apps with low or uneven traffic, many chains
Dedicated node	Only you	Flat monthly price	Steady heavy traffic, bots, indexers
Your own node	Only you	Server cost plus your time	Teams with someone to look after it

Public endpoints are tightly limited. Solana's public mainnet endpoint allows 100 requests every 10 seconds per IP address, and 40 for any one method, and its cluster docs say these endpoints "are not intended for production applications".

Shared plans lift those limits for a fee, but bill per request and cap requests per second. The dedicated vs shared RPC guide finds the traffic where a flat node becomes cheaper, and the RPC pricing index prices six providers for the same traffic.

CHAPTER 06

Running your own RPC node safely

The official docs agree: do not open the RPC port to the internet.

Keep the RPC port closed to the internet and put a proxy with a password or key in front of it. Geth's docs warn that bots constantly scan for open Ethereum nodes, and Bitcoin Core's docs say not to enable RPC over the public internet at all.

The warnings are blunt. Geth: "there are bots that continually scan for http-enabled Ethereum nodes to attack". Bitcoin Core: "Do not enable RPC connections over the public Internet", because its RPC was not hardened for arbitrary internet traffic and, without TLS in front of it, sends logins in clear text.

0 of 6 done

The RPC port listens on 127.0.0.1 or a private network, never on every addressA reverse proxy with HTTPS sits in front, and only it is reachable from outsideEvery request needs a key or password, checked by the proxyOnly the namespaces you use are on. Geth turns on only eth, net and web3 over HTTP by default; keep admin and debug offNo keys on the node. Sign transactions in the wallet or app, not on the RPC serverA firewall allows only the peer port the chain needs, plus your proxy

CHAPTER 07

What an RPC node costs on HeroRPC

A whole node, one flat price, ready within a day.

A dedicated RPC node on HeroRPC costs from $139 a month ($139 on Ethereum), with no per-request billing and no setup fee. Archive nodes start at $289. Your private endpoint is ready within 24 hours of payment.

Each node runs on its own server with a backup node beside it. The RPC port stays on localhost and your app reaches it through a private endpoint that needs your key, so the safety list above is already done. You also get the server logins, and you pay in crypto.

Pick a chain on the dedicated nodes page or compare every chain on node pricing.

QUESTIONS

RPC node questions

What is an RPC node in simple terms?

A blockchain node that answers questions from apps. Your wallet or app sends it a request, like "what is this balance?", and the node replies from its own copy of the chain. It also passes your signed transactions to the network.

What is the difference between an RPC node and an RPC endpoint?

The node is the server running the blockchain software. The endpoint is the address your app sends requests to. One endpoint can lead to one node, or to many nodes behind a load balancer on a shared plan.

Is an RPC node the same as a validator?

No. A validator makes or votes on blocks and usually needs stake. An RPC node answers app requests and does not take part in consensus. They can run the same software.

Does an RPC node need my private key?

No. Your wallet signs the transaction on your device and sends the signed result. The node only passes it on. Never put a private key on a server that answers RPC requests.

What port does an RPC node use?

It depends on the client. Geth uses 8545 for HTTP and 8546 for WebSocket, Bitcoin Core 8332, a local Solana node 8899 and 8900, and CometBFT 26657. These ports should stay closed to the internet, behind a proxy.

Can I use a free public RPC endpoint for my app?

For testing, yes. For a live app, no: public endpoints have tight limits (Solana's allows 100 requests per 10 seconds per IP) and Solana's own docs say they are not meant for production.

What does error -32601 mean?

Method not found. The node does not offer the method you called. Check the spelling, and check that the method is turned on for your node or plan.

ABOUT

How we made this guide

In October 2026 we sent one request to a public mainnet node of Ethereum, Solana, Bitcoin and the Cosmos Hub, plus one request with a misspelled method, and copied the replies as received (the Cosmos reply is shortened to the lines we explain). The endpoint is shown as a placeholder because any node of that chain answers the same way. Ports, error codes and warnings come from each project's own docs or code, checked in October 2026. HeroRPC prices are our own list prices.

Written by

HeroRPC team

Written and checked by the people who run HeroRPC's builder and node servers. Every figure links to its source.

Published 26 October 2026. Last updated 26 October 2026.

What is an RPC node? Real requests, real answers

What is an RPC node, in short?

What an RPC node does, and what it does not

How an RPC request works, with real answers

The parts of a request, a reply and an error

Error codes you will meet

Which block are you asking about?

HTTP, WebSocket and the ports each node uses

Public, shared, dedicated or your own RPC node

Running your own RPC node safely

What an RPC node costs on HeroRPC

RPC node questions

What is an RPC node in simple terms?

What is the difference between an RPC node and an RPC endpoint?

Is an RPC node the same as a validator?

Does an RPC node need my private key?

What port does an RPC node use?

Can I use a free public RPC endpoint for my app?

What does error -32601 mean?

How we made this guide

Get an RPC node that answers only you

What is an RPC node? Real requests, real answers

What is an RPC node, in short?

What an RPC node does, and what it does not

How an RPC request works, with real answers

The parts of a request, a reply and an error

Error codes you will meet

Which block are you asking about?

HTTP, WebSocket and the ports each node uses

Public, shared, dedicated or your own RPC node

Running your own RPC node safely

What an RPC node costs on HeroRPC

RPC node questions

What is an RPC node in simple terms?

What is the difference between an RPC node and an RPC endpoint?

Is an RPC node the same as a validator?

Does an RPC node need my private key?

What port does an RPC node use?

Can I use a free public RPC endpoint for my app?

What does error -32601 mean?

How we made this guide

Related guides

Get an RPC node that answers only you