SWIFT / BIC Code Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching swift / bic code, 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

# SWIFT / BIC Code
# ReDoS-safe | RegexVault — Finance > Bank Identifiers

import re

swift_bic_code_pattern = re.compile(r'^[A-Z]{4}[A-Z]{2}[A-Z0-9]{2}(?:[A-Z0-9]{3})?$')

def validate_swift_bic_code(value: str) -> bool:
    return bool(swift_bic_code_pattern.fullmatch(value))

# Example
print(validate_swift_bic_code("DEUTDEDB"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Bank Identifiers 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

Structure: 4-char bank code + 2-char country code + 2-char location code + 3-char branch code (optional, XXX = primary office). 8-char BICs are treated as 11-char with XXX suffix.