Base64 Encoded String

Matches a valid Base64-encoded string with proper padding using = characters.

✓ File upload validation✓ API token parsing✓ Image data URIs

Safe

Test String

No matches

SGVsbG8gV29ybGQ=
dGVzdA==
YWJjZGVmZ2g=

^^— ^ — start of string (or line in multiline mode)

(?:…)*Non-capturing group— Non-capturing group — groups without capturing (no index assigned) — repeated zero or more times (greedy) · * — zero or more times (greedy)

[…]{4}Character class […]— Matches any single character listed in this set — repeated exactly 4 times · {4} — exactly 4 times

(?:…)?Non-capturing group— Non-capturing group — groups without capturing (no index assigned) — repeated zero or one time (optional) · ? — zero or one time (optional)

[…]{2}Character class […]— Matches any single character listed in this set — repeated exactly 2 times · {2} — exactly 2 times

==— '=' — literal character

||— | — alternation: matches expression on left OR right

[…]{3}Character class […]— Matches any single character listed in this set — repeated exactly 3 times · {3} — exactly 3 times

==— '=' — literal character

$$— $ — end of string (or line in multiline mode)

Pattern: 67 charsInput: 38 chars

100% client-side · private

✓ Valid Examples

SGVsbG8gV29ybGQ=
dGVzdA==
YWJjZGVmZ2g=

✗ Invalid Examples

SGVsbG8gV29ybGQ
not!base64@string
YWJjZGVmZ2g===

Usage & Integration

Validate Base64 Encoded String natively in your backend or frontend without copying regex strings.

Node / Edge

import { validate } from '@regexto/validators';

validate('base64', '...');

Python

from regexto_validators import validate

validate("base64", "...")

Go

import "github.com/regex-to/validators-go"

valid, err := validators.Validate("base64", "...")

PHP

use RegexTo\Validators\Validator;

Validator::validate('base64', '...');

Rust

use regexto_validators::validate;

let is_valid = validate("base64", "...").unwrap();