Base64 Tools

Base64 Validator

Check alphabet, padding placement, length, canonical decode/re-encode behavior, decoded byte count, and detected variant locally.

Base64 or Base64URL

—Validity

—Detected alphabet

—Decoded bytes

—Canonical padding

ReadyChecks alphabet, padding placement, valid length, and canonical decode/re-encode behavior. It does not prove what the decoded bytes mean.

Strict Base64 structure, variant & decoded-byte inspection

Check alphabet, whitespace, padding and length rules before decoding. Detect standard versus URL-safe Base64, inspect decoded bytes and preview UTF-8 only when the byte sequence is valid text.

Base64 textVariantIgnore ASCII whitespace

—Validation

—Variant

—Decoded bytes

—Padding

Ready.

Validity has several layers

A string can use the Base64 alphabet yet still have invalid length, padding placement or non-canonical trailing bits. The validator checks those structural details and can decode/re-encode to catch ambiguous forms. Passing Base64 validation says nothing about what the decoded bytes mean.