Test JSON-RPC Calls Without Leaving Your Browser: The Playground Every Web3 Developer Needs

You're debugging a smart contract interaction. You need to test an eth_call. You need to check eth_getBalance for a specific address. You want to see what eth_getLogs returns for a particular event.

What do you do?

If you're like most developers, you open a terminal, fire up curl or a Python script, construct the JSON-RPC payload, hit the endpoint, parse the response, and repeat for every method you need to test. It works, but it's slow. And when you're in debugging mode, slow is the last thing you want.

The Friction of Traditional RPC Testing

JSON-RPC is the language blockchains speak. Every wallet, every dApp, every on-chain tool communicates through JSON-RPC calls. But testing these calls has always been unnecessarily cumbersome:

• Terminal workflows require remembering method signatures, parameter formats, and endpoint URLs
• No request history means you reconstruct the same calls every session
• No presets for common methods means typing out {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1} over and over
• Endpoint switching means updating URLs manually when you want to test against a different chain

What a Modern RPC Playground Looks Like

Browser-Based, Server-Proxy Powered

Send JSON-RPC requests directly from your browser. The platform handles the proxying server-side, so you never deal with CORS errors. Pick a chain, pick a method, send the request, get the response. That's the entire workflow.

Method Presets for Common Calls

Stop typing boilerplate. Pre-built templates for the methods you use most:

• eth_blockNumber — check current block
• eth_getBalance — query any address balance
• eth_call — execute read-only contract calls
• eth_getTransactionByHash — look up transactions
• eth_getLogs — filter event logs
• And more

Select a preset, fill in the parameters, send. Done.

Request History, Saved Locally

Every request you make is saved in your browser. Come back tomorrow, last week's test is still there. No accounts, no cloud storage, just local persistence that works.

Export as cURL

Need to share a test case with a teammate? Export any request as a ready-to-run cURL command. One click, copy, paste into terminal.

Who Benefits

• Smart contract developers testing contract interactions during development
• dApp engineers debugging frontend-to-blockchain communication issues
• Security researchers probing contract behavior with specific RPC calls
• Anyone who's ever typed a JSON-RPC payload by hand and thought "there has to be a better way"

It's Free and Requires No Setup

No API keys. No sign-up. No configuration. Open the page, pick a chain, start testing. The server-side proxy handles all the complexity of routing your requests to the right endpoints.

Find it at https://rpchub.top/playground