[ANN] raw₿it — Visual Raw Transaction Builder & Script Debugger (open-source)

[rawBit_io]

Hi everyone,

I’d like to share a project I’ve been working for the last year raw₿it — a visual raw transaction builder & script debugger.

https://rawbit.io

Source:https://github.com/rawBit-io/rawbit

It’s an interactive web application that lets you drag-and-drop predefined nodes on a canvas to build real Bitcoin transactions from scratch, with every byte updating live.

How it works:
The tool runs in your browser (calculations via lightweight backend) or fully offline with local install. Connect nodes to generate preimages, signatures, witnesses, TXID/WTXID, and more — no hex editing required. Step through script execution opcode by opcode and watch the stack change in real time.

Key Features: 
- Build transactions visually (P2PKH, multisig, timelocks, SegWit, etc.) 
- See the exact Python code behind every node 
- Change values and instantly update preimages, TXID, weight, fees 
- Multi-tab workspace, undo/redo, dark mode, shareable flows, testnet/mainnet/regtest switch 
- 10 hands-on lessons included (all transactions broadcast to testnet for verification) 


Disclaimer: 
This is an educational tool only — it is not designed or intended for handling real funds. Use it solely for learning and experimentation to avoid any risks.

Feedback, bug reports, and new lesson ideas welcome.

Thanks!

[BattleDog]

This looks really damn cool. I spent a good chunk of my early Bitcoin years hand-rolling raw tx hex in a terminal, copy-pasting into `sendrawtransaction`, then staring at some cryptic "TX decode failed" error because I messed up a single byte, lol.

Something like this would have saved me a lot of late-night swearing and a few sacrificed testnet coins.

A couple of selfish feature wishes from a grumpy old dev: descriptors/miniscript support would make this an amazing teaching tool for modern wallet design, and an easy way to export a PSBT or `bitcoin-cli` command from a flow would bridge the gap between "toy in the browser" and "I know what to type on a real node". Also, anything you can do to make the offline/local mode super obvious and frictionless is huge from an opsec point of view.

Anyway, nice work all 'round.

[rawBit_io]

This looks really damn cool. I spent a good chunk of my early Bitcoin years hand-rolling raw tx hex in a terminal, copy-pasting into `sendrawtransaction`, then staring at some cryptic "TX decode failed" error because I messed up a single byte, lol.

Something like this would have saved me a lot of late-night swearing and a few sacrificed testnet coins.

A couple of selfish feature wishes from a grumpy old dev: descriptors/miniscript support would make this an amazing teaching tool for modern wallet design, and an easy way to export a PSBT or `bitcoin-cli` command from a flow would bridge the gap between "toy in the browser" and "I know what to type on a real node". Also, anything you can do to make the offline/local mode super obvious and frictionless is huge from an opsec point of view.

Anyway, nice work all 'round.

Thank you for such thoughtful response! The idea for this project came from my own struggle with messing up bytes and forgetting the rules for different tx types after some time — that's when I got the idea that a visual tool with an integrated script debugger would be really helpful 

Thanks for the suggestions for new features — I'll look into when I can create nodes and lessons for descriptors/miniscript and PSBT. 

Regarding your suggestion about bitcoin-cli commands, it is already partially there — for example, in Flow Examples > "Intro P2PKH", the node "Final Raw Transaction (ready to broadcast)" shows the comment 'bitcoin-cli -testnet sendrawtransaction <hex>', and the raw tx hex can be copied with the copy button. Actually, at some point I had an RPC node that talked to locally installed Bitcoin Core and could send tx to the network, but I decided against it, so sending should be a really conscious operation. 

Regarding making offline mode super easy — good idea, I'll think about a simple solution, because it can be used locally now but you need to install both the frontend and backend.

[ABCbits]

I only tried it a bit, but it's probably most interesting project i've seen in this forum in past few months.

- See the exact Python code behind every node 

It seems it doesn't show full reference/code. Using example on below screenshot, i have no idea where variable such as SECP256k1 come from. The space on line 11 also looks unusual, but i don't whether it's intentional or just formatting bug.   

Feedback, bug reports, and new lesson ideas welcome.

While exploring few "Flow Examples", i notice there are so many nodes which makes navigation isn't easy. Maybe using multiple color for line that connect 2 nodes could slightly improve issue i experienced.

[rawBit_io]

I only tried it a bit, but it's probably most interesting project i've seen in this forum in past few months.

- See the exact Python code behind every node  

It seems it doesn't show full reference/code. Using example on below screenshot, i have no idea where variable such as SECP256k1 come from. The space on line 11 also looks unusual, but i don't whether it's intentional or just formatting bug.  

https://i.ibb.co/BVJ224CF/a.png

Feedback, bug reports, and new lesson ideas welcome.

While exploring few "Flow Examples", i notice there are so many nodes which makes navigation isn't easy. Maybe using multiple color for line that connect 2 nodes could slightly improve issue i experienced.

Thanks for the kind response and the detailed feedback!

You're right about line 11 — that's a display bug in the code viewer, not the actual code. I'll fix the rendering to handle long lines properly.

Regarding missing imports like SECP256k1 — good catch. Currently, the popup only shows the function body, so it's confusing when variables seem to come from nowhere. I'll adjust the rendering to include relevant imports at the top.

Regarding colored edges — I tried this early on, but it looked chaotic with complex flows. There's a feature that might help though: clicking any edge highlights both connected nodes. Navigation gets easier after working with the app for a bit, but I'm open to revisiting this if more users find it difficult.

edit1:
I've just created a quick demo of colored edges in raw₿it — check it out on YouTube: https://www.youtube.com/watch?v=10JHjvhVYbc
The video also shows node highlighting when you select an edge.

If you find this helpful, let me know — I'll include it in the next public release.

[ABCbits]

--snip--
Regarding colored edges — I tried this early on, but it looked chaotic with complex flows. There's a feature that might help though: clicking any edge highlights both connected nodes. Navigation gets easier after working with the app for a bit, but I'm open to revisiting this if more users find it difficult.

edit1:
I've just created a quick demo of colored edges in raw₿it — check it out on YouTube: https://www.youtube.com/watch?v=10JHjvhVYbc
The video also shows node highlighting when you select an edge.

If you find this helpful, let me know — I'll include it in the next public release.

Thanks for showing the video demo. IMO the colored line/edge somewhat helpful for navigation, although i would also suggest to seek more opinion.

[rawBit_io]

short demo video (50 seconds):
Shows building ScriptPubKey + stepping through the script debugger with live stack view.

https://www.youtube.com/watch?v=n4YHoKj4Ics

[rawBit_io]

In this video, I walk through creating a legacy P2PKH (Pay-to-Public-Key-Hash) transaction using rawBit.

https://www.youtube.com/watch?v=0A6m_jMDrh0

Full interactive lesson https://rawbit.io/?s=s1_LNxiSD_yMBs 

The complete lesson includes
 - P2PK vs P2PKH script differences
 - Multi-output transactions (payment + change)
 - Spending from multiple inputs
 - Script verification step-by-step