TASK

Decode Base64 text and handle missing or corrupted padding

Decode Base64 payloads that arrive without trailing '=' padding or with URL-safe alphabet, and recover the original bytes safely.

1

Base64 encodes every 3 bytes into 4 characters; when the input length is not a multiple of 3, padding '=' characters are added. Some APIs strip the padding or swap +/ for -_ (URL-safe alphabet). Decoding must restore both before processing.
2

Base64 Decoder →
Paste the Base64 string. If padding is missing the decoder auto-restores it; if the alphabet is URL-safe (- and _), toggle the variant option.
3

base64-encode → base64-decode
View recipe Open in Toolchain

Run the round-trip chain to confirm your decode output re-encodes to the same input — this catches silent corruption from wrong alphabets.
4

If the decoded bytes look like binary (not text), switch the output mode to hex or save to file via the base64-to-file tool to inspect the raw bytes.

Frequently asked questions

Why does my decoded text contain replacement characters?: The decoded bytes are likely not UTF-8 text. Try interpreting as Latin-1, or treat the output as binary and save to a file to inspect its actual content.
What is the difference between standard and URL-safe Base64?: Standard uses + and / with = padding; URL-safe replaces + with - and / with _, and often omits padding. Both encode the same bytes — only the alphabet differs.

Workflows that solve this

Convert Ascii85 to Base64

Decode Ascii85 and re-encode as Base64 for wider compatibility.

Convert Base2048 to Base64

Decode Base2048 (emoji) and re-encode as Base64 for standard transport.

Convert Base32 to Base64

Decode a Base32-encoded string into raw bytes and re-encode as Base64 for more compact representation.

Convert Base58 to Base64

Decode Base58 and re-encode as Base64 for standard compatibility.

Base64 encode then decode round-trip

Encode text to Base64 and decode it back to verify the round-trip preserves the original data.

Convert Base64 to Base85

Decode Base64 and re-encode as Base85 for compact representation.

Convert Base64 to Hex

Decode a Base64 string into raw bytes and re-encode it as hexadecimal for inspection or interop.

Blowfish Encrypt then Base64

Blowfish encrypt then Base64-encode for text-safe transport.

Decode a Basic Auth credential pair

Decode the Base64 portion of an HTTP Basic Authorization header into username:password.

DES Encrypt then Base64

DES encrypt then Base64-encode for legacy compatibility.

Encode a JSON payload for URL transport

Prepare a JSON document for a URL parameter: pretty-print, Base64-encode, then percent-encode — the exact inverse of the nested-parameter decode chain.

AES encrypt then Base64 encode

Encrypt plaintext with AES and encode the ciphertext as Base64 for text-safe transport.

Hash content and encode as Base64

Compute a hash of the input and encode the hash digest as Base64 for compact transport.

Convert Hex to Base64

Decode a hexadecimal string into raw bytes and re-encode it as Base64 for compact transport.

HMAC Sign then Base64 Encode

Generate HMAC signature then Base64-encode for API auth headers.

Morse Encode and Base64 Transport

Encode text as Morse code then Base64-encode for digital transport.

Decode and format a JWT payload

Parse a JWT token, extract its payload, and format the JSON for inspection.

RC4 Encrypt then Base64

RC4 encrypt then Base64-encode for transport.

RIPEMD-160 Hash then Base64

Compute RIPEMD-160 hash then Base64-encode for transport.

Shuffle Text and Base64 Encode

Shuffle text characters then Base64-encode the result.

Unicode Escape and Base64 Encode

Unicode-escape text then Base64-encode for ASCII-safe transport.

URL Encode then Base64 Double Encode

URL-encode then Base64-encode for double encoding in API payloads.

Decode nested URL parameter (Base64 JSON)

Unwrap a URL parameter that carries URL-encoded Base64 JSON into readable, formatted JSON.

UUencode then Base64

UUencode text then Base64-encode the result for double encoding.

Generate UUID and Base64 Encode

Generate a UUID then Base64-encode it for compact storage.

Learn more

Want to understand why?

Base64: how it works and when to use it

The byte-to-character mechanics behind Base64, why padding exists, which alphabet variants you will meet, and the boundaries where Base64 is the wrong tool.

How to Base64 Decode Text

Learn to reverse a Base64 string back to its original form, including how to handle padding and invalid characters.

Base64 maps arbitrary binary data onto 64 printable ASCII characters (A-Z, a-z, 0-9, +, /) so that binary data can travel over text-only channels.

Base64 Padded (PH)

Base64 Padded denotes the standard Base64 variant that strictly keeps its = padding characters, so the output length is always a multiple of 4.

Related tools

Decode Base64 data back to readable text online. Free, private, and 100% client-side.

Encode text or binary data to Base64 online. Free, private, and 100% client-side.

Decode Base64 data URL to downloadable file. Free, private, 100% client-side.