Home

Casper (CSPR) API Documentation

Casper

Casper (CSPR) is an account-based Layer 1 smart contract platform secured by proof-of-stake validators, with Casper 2.0 replacing the original Highway consensus protocol with Zug. On-chain code can be written in languages that compile to WebAssembly, commonly Rust, while nodes execute Wasm and maintain accounts, contracts, transactions, and global state. This Wasm-based execution model separates application code from a single source language, so integrations center on Casper’s native account, transaction, contract, and state-query abstractions rather than EVM semantics.

Casper API Methods and Endpoints

NOWNodes exposes Casper's interface, plus a few others, depending on what your integration needs: JSON-RPC for reading chain state and broadcasting transactions.

Browse the interfaces below for endpoint details, request parameters, response formats, and integration examples. Create an API key, select Mainnet or Testnet, choose the required interface, and start sending requests from your application.

Weighing Casper RPC providers against each other? Read the comparison guide on our blog — this page stays focused on integration reference.

Quick start

01

Get an API key

Sign up and generate a free key from the dashboard.

Get key →
02

Select environment

Mainnet or Sepolia testnet.

03

Choose an interface

RPC, WSS, Blockbook, or Trace/Debug.

04

Send a request

Call it from your application.

RPCJSON-RPCStandard RPC methods for reading chain state and broadcasting transactions.Node APIs →WSSWebSocketPersistent connections for new blocks, pending transactions, and log events as they happen.WSS API →T/DTrace & DebugStep-level execution traces for inspecting calls and diagnosing transactions.Trace & Debug API →ARCArchive modeFull historical state access beyond standard node retention.Archive nodes →MCPModel Context ProtocolThe Model Context Protocol (MCP) is an open standard that lets AI assistants call external tools through a uniform interface.MCP →

Ready to build on: CSPR

Create a free API key and start sending requests in minutes.

Get free API keyDashboard