Base64 UTF-8

base64-utf8 · version 1.0.0 · Encoding & checksums · free, no key needed

Decode standard Base64 to UTF-8 text. Transformation only; no security claim.

Use when you need to: base64 utf8 · base64 decode utf8 · decode base64 text.

Supported

• base64 utf8
• base64 decode utf8
• decode base64 text

Not supported

• base64url
• ignore whitespace
• compression
• encryption

Behavior

• Input must be standard Base64: alphabet A-Za-z0-9+/, length multiple of 4 (empty allowed), padding only at end as required, no whitespace.
• Reject URL-safe alphabet, missing padding, extra padding, and non-canonical leftover bits.
• Decoded bytes must be valid UTF-8; reject overlong encodings and invalid sequences.
• This is a byte transform, not confidentiality or authenticity.

Input

• base64 (string, required): max length 256000

Output

• text (string, required)

Limits

• max input bytes: 256000

Example

Request input:

{
  "base64": "TWFu"
}

Response:

{
  "result": {
    "text": "Man"
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "base64-utf8",
  "version": "1.0.0",
  "input": {
    "base64": "TWFu"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/base64-utf8/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"base64":"TWFu"}'

The machine-readable contract is at /v1/tools/base64-utf8/versions/1.0.0.

CLI

node cli.mjs run base64-utf8 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• UTF-8 Base64: Encode a Unicode string as standard Base64 of its UTF-8 bytes. Transformation only; no security claim.
• UTF-8 hex: Encode a Unicode string as lowercase hex of its UTF-8 bytes. Transformation only; no security claim.
• Adler-32: Adler-32 of UTF-8 bytes (RFC 1950). Integrity check only; no security claim.
• CRC-32: CRC-32 of UTF-8 bytes (ISO 3309 / ZIP / PNG polynomial). Integrity check only; no security claim.
• Hex bytes concat: Concatenate a bounded ordered list of lowercase hex byte strings into one hex string.
• Hex bytes slice: Slice a lowercase hex byte string by explicit byte-index bounds, half-open like Array.slice.