Pattern
/(?:[A-Za-z0-9+/]{4}){4,}(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?/Sample text
SGVsbG8gUGF0dGVybkxhYiE= short YWJjZGVmZ2hpams=Test this pattern in the editor
Base64 blobs
Longish base64 strings with optional padding.
Related patterns
Strong-ish password
Require length and mixed character classes (demo only).
UUID
Standard 8-4-4-4-12 hex UUID layout.
UUID v4
Stricter UUID version 4 with variant bits.
Credit card numbers
13–19 digit groups (Luhn not validated).
Percentages
Integer or decimal percentage values.
Quoted CSV fields
Capture double-quoted CSV fields.