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Validation · Tier 2

Credit Card (Simple)

Matches major credit cards (Visa, MasterCard, Amex, Discover).

Answer Capsule

Credit Card (Simple) helps validate values with a production-oriented regex baseline. Use it for fast client or backend checks, then add semantic validation and engine-specific tests before release. This reduces false positives while keeping implementation predictable across environments.

Regex Block
^(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|3[47][0-9]{13}|6(?:011|5[0-9]{2})[0-9]{12})$

Compatibility Badges

PCRE JavaScript Python Java

Token Explanation

Token-by-token with plain language, one sentence per token group.

  • `^` anchors matching at the start.
  • `$` anchors matching at the end.
  • `?` enables optional or lazy behavior.
  • `|` adds alternation branches.

Edge Cases And Caveats

  • Very long input strings can impact performance if Credit Card (Simple) is used without anchors.
  • Unicode and locale edge cases should be tested in the exact runtime engine before rollout.
  • Always include rejected examples in tests to prevent false positives during refactors.

Test Cases

Input Expected
4111111111111111 Pass
123 Fail
Fail
sample-value Fail
test@example.com Fail
1234567890 Pass

Engine Variants

PCRE

Reference implementation.

JavaScript

Re-test lookbehind, unicode, and flags.

Python

Prefer raw strings and explicit flags.

Java

Double-escape backslashes in string literals.

FAQ

When should I use the Credit Card (Simple) regex?

Use this when you need a quick format validation or extraction step before business-level checks.

Is this pattern cross-engine compatible?

Core behavior is designed for broad compatibility, but always re-test flags and advanced groups in your target engine.

What should I avoid with this pattern?

Avoid treating regex as the only safety check. Pair it with parser or domain-specific validation for production flows.

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