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Interacting with the Casper JSON-RPC API

Users looking to interact with the JSON-RPC API of a Casper network have several options, depending on their needs and the level of interaction required.

Using a Casper SDK

The Casper Association provides a JavaScript SDK for use with Casper networks. A list of additional SDKs maintained by third parties can be found here.

These SDKs offer a means to build decentralized applications by interacting with the JSON-RPC API through your programming language of choice.

Building a Casper SDK

Most programming languages that compile to WebAssembly (Wasm) are compatible with Casper. If there is not currently an SDK for your preferred programming language, you are free to build your own Casper SDK Standard compliant SDK.

The standard outlines necessary available endpoints and their included types, both for fully-featured SDKs and those of a more narrow scope. Guidance for Casper SDK developers can be found here.

Interacting Directly with the JSON-RPC

For advanced users that wish to interact directly with the JSON-RPC API, they are free to do so using various tools like Postman.

The Casper JSON-RPC API is fully compatible with the JSON-RPC 2.0 Specification.

Casper nodes provide the RPC schema on port 8888, followed by rpc-schema:


To see an example, navigate to in your browser.

The Casper client subcommand list-rpcs provides all currently supported RPCs. Here is an example of running the Casper client to list RPCs:

casper-client list-rpcs -n