Bitcoin Address (P2SH — starts with 3) Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching bitcoin address (p2sh — starts with 3), ported and verified for Python. Financial data validation has zero tolerance for false negatives — a missed invalid entry can corrupt downstream calculations. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# Bitcoin Address (P2SH — starts with 3)
# ReDoS-safe | RegexVault — Finance > Crypto

import re

bitcoin_address_p2sh_starts_with_3_pattern = re.compile(r'^3[a-km-zA-HJ-NP-Z1-9]{25,34}$')

def validate_bitcoin_address_p2sh_starts_with_3(value: str) -> bool:
    return bool(bitcoin_address_p2sh_starts_with_3_pattern.fullmatch(value))

# Example
print(validate_bitcoin_address_p2sh_starts_with_3("3J98t1WpEZ73CNmQviecrnyiWrnqRhWNLy"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Crypto category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

P2SH addresses start with 3. Commonly used for multisignature wallets and wrapped SegWit (P2SH-P2WPKH). More flexible than P2PKH — can represent complex spending conditions.