For developers

Stop Fighting Raw Opcodes. Ship Bitcoin Script This Weekend.

Bitcoin-SX is the IDE that turns Bitcoin Script from a stack-based puzzle into real, debuggable software. Write in SX, simulate every branch, and broadcast to testnet without leaving your browser.

Start Building FreeTry it in the browser

The problem

You didn't get into Bitcoin development to reverse-engineer hex dumps. Raw Script gives you no variables, no functions, no stack trace, just a wall of opcodes and a silent failure when something's wrong.

Bitcoin-SX gives you a real language on top of Script: named arguments, loops, macros, a standard library that already handles the ugly cryptographic plumbing, and a step-through debugger that shows you the stack at every single operation.

What you get

Readable SX syntax: Named arguments and labeled stack values instead of positional opcodes you have to count by hand.
Importable standard library: Signature and context verification are already written. Import them instead of re-deriving the cryptographic plumbing.
Step-through simulator: Walk the stack one operation at a time, with specific, actionable errors rather than a silent failure.
The whole stack from one project: The same project generates a typed API and a React frontend alongside the contract.
One-click GitHub commit: Commit and push straight from the IDE, so your contract history lives in your own repo.
Usage-based hour packs: No subscription, and hours never expire. You pay for the time you actually spend building.

The editor

This is a P2PKH contract. All of it.

Named values, not stack positions: The left pane is SX source. Arguments have names, so you are reading intent rather than counting positions on a stack.
The stack, on the right, always: The Stacks panel tracks main and alt stacks as you step, with hex or decimal display. It is the state you would otherwise be holding in your head.
Tabs are one project, not five: Editor, Simulator, Transactions, Wallet, Prompt, API and Front are views of the same contract, which is why the API and frontend stay in sync with it.

The Bitcoin-SX editor showing p2pkh.sx source alongside the stack panel

Inside the IDE

Simulator with contract-arguments panel. Step through execution one operation at a time and inspect the stack at every point before anything is broadcast.

Transactions and broadcast panel. The constructed transaction, inspectable before it is sent. Testnet first, by default.

Try it now

Run it in the browser before you sign up for anything.

Open the full editor in a new tab

Frequently asked questions

If something you need to know isn't here, just ask. We'd rather answer directly than leave you guessing.

Try it in the browser

No. SX is designed so you can write a working contract without hand-writing opcodes, and the step-through simulator shows you the stack at each operation, which is how most people end up learning what the underlying Script is actually doing. Knowing Script certainly helps, but it isn't the entry requirement.