TSS_Create_PSBT

A simple, open-source API to help you create and send Bitcoin payments using PSBTs (Partially Signed Bitcoin Transactions). This project is designed for both beginners and advanced users who want to automate or scale Bitcoin payments for orders, e-commerce, or any use case.

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🚀 Features

• Create PSBTs for Bitcoin transactions
• Configurable fees (flat or fee rate)
• Bulk and single transaction support
• Multi-output PSBTs
• Easy to run locally or in production
• Secure by design (no private keys handled)

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🛠️ Quick Start (For Beginners)

1. Clone the Repository

git clone https://github.com/yourusername/TSS_SendBitcoin.git
cd TSS_SendBitcoin

2. Set Up Python Environment

Create a virtual environment (recommended):

python3 -m venv venv
source venv/bin/activate

3. Install Dependencies

pip install -r requirements.txt

4. Configure Environment Variables

Create a .env file in the project root (or set them in your shell):

# .env
INDEXER_API_KEY="your_api_key"  # Only needed if you use inscriptionId lookups
INDEXER_BASE="https://open-api-fractal.unisat.io/v1/indexer/inscription/info/"
MIN_UTXO_VALUE="330"
DEFAULT_FLAT_FEE="200"
SKIP_INSCRIPTIONS="false"
SKIP_546_UTXOS="false"
PORT="8000"

5. Run the Server

python3 app.py

The server will start at http://localhost:8000 by default.

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🧪 How to Test the API

A. Test with curl (Command Line)

Single Transaction Example

curl -X POST http://localhost:8000/create_psbt \
  -H 'Content-Type: application/json' \
  -d '{
        "utxos": [{"txid":"1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef","vout":0,"value":10000,"scriptPubKey":"0014abcdef1234567890abcdef1234567890abcdef12"}],
        "outputs": [{"address":"bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh","amount":9000}],
        "fee":200
      }'

Single PSBT with Multiple Outputs Example

curl -X POST http://localhost:8000/create_psbt \
  -H 'Content-Type: application/json' \
  -d '{
        "utxos": [{"txid":"1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef","vout":0,"value":10000,"scriptPubKey":"0014abcdef1234567890abcdef1234567890abcdef12"}],
        "outputs": [
          {"address":"bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh","amount":5000},
          {"address":"bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh","amount":3000}
        ],
        "fee":200
      }'

Batch/Bulk Transactions

Prepare a file (e.g. bulk_requests.json) with multiple requests (see examples/bulk_requests.json):

[
  { "utxos": [...], "outputs": [...], "fee": 200 },
  { "utxos": [...], "outputs": [...], "fee_rate": 1.5 }
]

Then loop through them:

cat bulk_requests.json | jq -c '.[]' | while read req; do
  curl -X POST http://localhost:8000/create_psbt \
    -H 'Content-Type: application/json' \
    -d "$req"
done

B. Test with Postman (GUI)

1. Open Postman
2. Create a new POST request to http://localhost:8000/create_psbt
3. Set body to raw and JSON, then paste your request data
4. Click Send and view the response

C. Run Automated Tests

python3 -m pytest tests/

All tests should pass if your setup is correct.

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📝 API Reference

POST /create_psbt

• utxos: List of UTXOs to spend (each with txid, vout, value/satoshi, scriptPubKey)
• outputs: List of outputs (each with address, amount)
• fee: (optional) Flat fee in sats
• fee_rate: (optional) Fee rate in sats/vbyte
• inscriptionId: (optional) If provided, fetches the UTXO for this inscription

Returns:

• psbt: The base64-encoded PSBT string
• fee: Fee used
• change: Change output (if any)
• inputs_used: Number of UTXOs used
• fee_rate and vsize if fee_rate was used

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🔒 Security Best Practices

• Never expose private keys to this server
• Use HTTPS in production
• Protect your API keys (do not commit them)
• Validate all input if you modify the code
• Run behind a firewall if on a public server

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🧑‍💻 For Developers: How to Build On Top

• Fork or clone this repo
• Add new endpoints or logic in app.py
• Write new tests in tests/
• Use the PSBT output with your own signing wallet or service

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📂 Project Structure

TSS_SendBitcoin/
├── app.py                  # Main Flask API
├── requirements.txt        # Python dependencies
├── README.md               # This file
├── LICENSE                 # MIT License
├── tests/                  # Automated tests
│   └── test_psbt_creator.py
├── examples/
│   └── bulk_requests.json  # Example batch requests
└── .gitignore

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🤝 Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/my-feature)
3. Commit your changes (git commit -am 'Add new feature')
4. Push to the branch (git push origin feature/my-feature)
5. Open a Pull Request

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📜 License

MIT — see LICENSE

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💬 Need Help?

• Open an issue on GitHub
• Or start a discussion!

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TSS: Bitcoin scripting made simple and open-source, scalable, and easy for everyone.