Cosmos

GetBlock provides fast and reliable access to Cosmos nodes via JSON-RPC API. Connect to the Cosmos network without running your own infrastructure.

Cosmos Hub is the flagship blockchain of the Cosmos ecosystem — the "Internet of Blockchains" — and the original implementation of the Cosmos SDK and CometBFT (formerly Tendermint Core) consensus engine.

Launched in March 2019 by the Interchain Foundation following the Cosmos whitepaper, the network pioneered application-specific Layer 1 design and the Inter-Blockchain Communication protocol (IBC), which today connects 100+ sovereign chains.

The Hub itself secures Interchain Security (replicated security for consumer chains), hosts the ATOM token, and serves as the economic and governance center of the broader Cosmos network. Under the hood, Cosmos Hub runs the CometBFT consensus engine — a deterministic, Byzantine fault-tolerant state-machine replication engine — which exposes a well-defined RPC surface that this documentation covers.

Key Features

• CometBFT Consensus: Deterministic instant finality (one block = final) via Tendermint-style BFT consensus — no fork choice, no probabilistic confirmation windows

• Cosmos SDK Architecture: Modular blockchain framework built around specialized modules (bank, staking, gov, distribution, slashing, ibc)

• Inter-Blockchain Communication (IBC): First-class native interoperability with 100+ Cosmos ecosystem chains

• Interchain Security: The Hub leases its validator set to consumer chains, providing replicated security as a service

• ATOM Token: Native staking, governance, and IBC fee asset (uatom — 6 decimals)

• Bech32 Addresses: Human-readable cosmos1... addresses, with chain-specific prefixes for IBC-connected chains

• PoS Validator Set: ~180 active validators secure the network with delegated proof-of-stake

• 6-Second Block Time: Predictable ~6s block production with single-slot finality

• Liquid Staking: Native support for liquid-staked ATOM derivatives (stATOM, stkATOM) via IBC-connected liquid staking chains

• Governance On-Chain: ATOM holders vote on protocol upgrades, parameter changes, and community spend proposals

TECHNICAL DISCLAIMER: AUTHORITATIVE COMETBFT RPC SPECIFICATION

GetBlock’s Cosmos Hub API reference documentation is provided exclusively for informational purposes and to optimize the developer experience. The canonical and normative specification for the CometBFT RPC interface is maintained by the CometBFT team and published at docs.cometbft.com/main/spec/rpc, with upstream source at github.com/cometbft/cometbft. For Cosmos SDK protocol details, module specifications, and the IBC protocol, consult the official Cosmos documentation.

SCOPE: COMETBFT RPC ONLY — REST / LCD IS A SEPARATE PRODUCT

GetBlock exposes three distinct APIs for Cosmos Hub:

1. CometBFT JSON-RPC (this documentation)

2. Cosmos REST / LCD (HTTP GET to paths like /cosmos/bank/v1beta1/balances/{address}),

3. CometBFT WebSocket (for event subscriptions).

This package documents only the CometBFT RPC and WebSocket. The Cosmos REST API is a separate, very large surface auto-generated from each Cosmos SDK module's gRPC services (cosmos.bank, cosmos.staking, cosmos.gov, cosmos.distribution, etc.) and deserves its own dedicated documentation package. To browse REST endpoints today, use the official Cosmos REST API reference.

Network Information

Property	Value
Network Name	Cosmos Hub Mainnet
Chain ID	cosmoshub-4
Native Currency	ATOM
Denomination	uatom (1 ATOM = 1,000,000 uatom — 6 decimals)
Block Time	~6 seconds
Consensus	CometBFT (Byzantine fault-tolerant; instant finality)
Active Validators	~180
Address Format	Bech32 cosmos1... (validator: cosmosvaloper1...)
Block Explorer	mintscan.io/cosmos, atomscan.com

Base URL

Frankfurt, Germany

https://go.getblock.io/<ACCESS-TOKEN>/

CometBFT supports three transports for the same methods:

• JSON-RPC over HTTP (POST) — sends a JSON-RPC 2.0 body to the base URL with the method field selecting the operation. Default in this documentation.

• URI over HTTP (GET) — appends the method name as a path segment (e.g. /status, /block?height=12345). Useful for browser debugging and one-off cURL calls. Most pages include a GET variant in the cURL tab where applicable.

• JSON-RPC over WebSocket — for real-time event subscriptions at wss://go.getblock.io/<ACCESS-TOKEN>/websocket. Used for subscribe / unsubscribe / unsubscribe_all.

Supported Networks

Network	JSON-RPC	WSS	URI (GET)	Frankfurt, Germany
Mainnet	✅	✅	✅	✅

Quickstart

In this section, you will learn how to make your first call with either:

• Axios (JavaScript / Node.js)

• Python (Requests library)

Before you begin, you must have already installed npm or yarn on your local machine (for the Axios example) or Python and pip (for the Python example).

JavaScript (Axios)

1

Setup project

mkdir cosmos-api-quickstart
cd cosmos-api-quickstart
npm init --yes

2

Install Axios

npm install axios

3

Create file

Create a new file named index.js. This is where you will make your first call.

4

Set ES module type

Set the ES module "type": "module" in your package.json.

5

Add code

index.js

import axios from 'axios';

const data = JSON.stringify({
    "jsonrpc": "2.0",
    "method": "status",
    "params": [],
    "id": "getblock.io"
});

const config = {
    method: 'post',
    url: 'https://go.getblock.io/<ACCESS-TOKEN>/',
    headers: {
        'Content-Type': 'application/json'
    },
    data: data
};

axios(config)
    .then(response => console.log(JSON.stringify(response.data, null, 2)))
    .catch(error => console.log(error));

Replace <ACCESS-TOKEN> with your actual GetBlock access token.

6

Run the script

node index.js

Expected output (truncated):

{
    "jsonrpc": "2.0",
    "id": -1,
    "result": {
        "node_info": {
            "protocol_version": {
                "p2p": "8",
                "block": "11",
                "app": "0"
            },
            "id": "d22eecb26c324945056c1528f558580a3213937d",
            "listen_addr": "tcp://0.0.0.0:26656",
            "network": "cosmoshub-4",
            "version": "0.38.19",
            "channels": "40202122233038606100",
            "moniker": "9f5085e21705",
            "other": {
                "tx_index": "on",
                "rpc_address": "tcp://0.0.0.0:26657"
            }
        },
        "sync_info": {
            "latest_block_hash": "613E4F90A9B1772F527B94D25FC84E33D91B913A3DA38D247CE8A36710EA0257",
            "latest_app_hash": "F8841DAC63C6987DCED0B79B992134BF79DD15B47FC191DB75BB65A82657ACE9",
            "latest_block_height": "31378844",
            "latest_block_time": "2026-06-01T10:31:22.184767269Z",
            "earliest_block_hash": "4762CB4F2BFC2462911D0777D160D25CBF426343C831DFA26F35A31B371D1804",
            "earliest_app_hash": "807931A4854E57D9EB859695AD49D8DAD11B1D81A037E015F4ECEA168B53C3EC",
            "earliest_block_height": "26165371",
            "earliest_block_time": "2025-06-13T21:29:05.414994118Z",
            "catching_up": false
        },
        "validator_info": {
            "address": "8BFAB70EC8F05E6B106BEBD3F3F7F9F3797CD35C",
            "pub_key": {
                "type": "tendermint/PubKeyEd25519",
                "value": "f1m/S2ZdJmgDXX1YJWXmd+q28EPkYKu5OAL3zayoGsY="
            },
            "voting_power": "0"
        }
    }
}

network: "cosmoshub-4" and catching_up: false confirm you are connected to a synced Cosmos Hub mainnet node.

Python (Requests)

Available API Methods

CometBFT exposes ~24 RPC methods covering node info, block/chain data, transaction handling, mempool, ABCI queries, and event subscriptions.

Node Info & Health

Method	Description
health	Returns empty result if the node is healthy; otherwise an error
status	Returns node info, pubkey, latest block hash, app hash, block height/time
net_info	Returns network info (peers, listeners, p2p stats)

Blocks & Chain

Method	Description
blockchain	Returns block metadata for a range of blocks
block	Returns block at a specific height
block_by_hash	Returns a block by its hash
block_results	Returns the results of all transactions in a block
commit	Returns the commit (signatures) for a block
header	Returns a block header at a specific height
header_by_hash	Returns a block header by its hash

Consensus & Validators

Method	Description
validators	Returns the validator set at a specific height
consensus_state	Returns the current consensus state
dump_consensus_state	Returns the full consensus state (validators, votes, peers)
consensus_params	Returns consensus parameters at a specific height
genesis	Returns the genesis document (small chains only)
genesis_chunked	Returns the genesis document in chunks (for large chains like Cosmos Hub)

Transactions

Method	Description
tx	Returns a transaction by hash, with optional inclusion proof
tx_search	Searches transactions by event-attribute query
block_search	Searches blocks by event-attribute query
broadcast_tx_sync	Broadcasts a transaction and returns after CheckTx (synchronous)
broadcast_tx_async	Broadcasts a transaction and returns immediately (asynchronous)
broadcast_tx_commit	Broadcasts a transaction and waits until it is committed in a block
check_tx	Runs a CheckTx against the application without broadcasting

Mempool

Method	Description
unconfirmed_txs	Returns transactions in the mempool
num_unconfirmed_txs	Returns the count and size of transactions in the mempool

ABCI Application Queries

Method	Description
abci_info	Returns information about the ABCI application
abci_query	Runs an ABCI query against the application (used by Cosmos SDK gRPC layer)

WebSocket Subscriptions

Method	Description
subscribe	Subscribes to events matching a Tendermint event query
unsubscribe	Cancels a specific subscription
unsubscribe_all	Cancels all subscriptions on the connection

Support

For technical support and questions:

• Support Email: [e-mail]

See Also

• Official Cosmos Documentation

• CometBFT RPC Reference

• Cosmos REST API Reference — separate API surface, not covered in this package

• Mintscan Explorer

• Atomscan Explorer

• Cosmos Chain Registry

• CosmJS (JavaScript SDK)

• cosmpy (Python SDK)

• Cosmos SDK Module Specifications

• IBC Protocol Documentation