Discover Card Number Regex for Python

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching discover card number, 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

# Discover Card Number
# ReDoS-safe | RegexVault — Finance > Card Numbers

import re

discover_card_number_pattern = re.compile(r'^(?:6011[0-9]{12}|64[4-9][0-9]{13}|65[0-9]{14}|622(?:1(?:2[6-9]|[3-9][0-9])|[2-8][0-9]{2}|9(?:[01][0-9]|2[0-5]))[0-9]{10})$')

def validate_discover_card_number(value: str) -> bool:
    return bool(discover_card_number_pattern.fullmatch(value))

# Example
print(validate_discover_card_number("6011111111111117"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Card Numbers 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

Discover has multiple BIN ranges. The 622126-622925 range (UnionPay cobranded) was added later. Some validators miss the 644-649 and UnionPay ranges.