Description
Look up one symbol in a selected RFC 4648 alphabet.
Encoded representations separate alphabet symbols, numerical digit values, byte grouping and tail padding. Recognizing one symbol or pad-bit pattern is not full payload decoding, and different alphabet variants can assign different values.
Look up one symbol in a selected RFC 4648 alphabet.
When to use this tool
Use RFC 4648 Alphabet Symbol Index when inspecting one stated alphabet, group or padding component.
How to use the tool and how it works
- Enter symbol, alphabet. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read recognized, index. Inspect recognized before interpreting the associated values.
Look up one symbol in a selected RFC 4648 alphabet. Accept base16/base32/base32hex/base64/base64url and a one-character symbol; return recognized and index, using -1 when absent.1
Canonical Base-N encodings require unused pad bits to be zero; alphabet membership alone does not establish canonical encoding.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| symbol | One symbol from the stated alphabet; matching uses the stated case convention. | Required. Text; maximum UTF-16 length 8192. |
| alphabet | Alphabet | Required. Text; one of "base16", "base32", "base32hex", "base64", "base64url"; maximum UTF-16 length 8192. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| recognized | Recognized | Required. Boolean. |
| index | Position under the stated indexing convention; inspect any missing-value sentinel. | Required. Safe integer. |
{
"input": {
"symbol": "V",
"alphabet": "base32hex"
},
"output": {
"recognized": true,
"index": 31
}
}Limitations and assumptions
- Base16/Base32 variants here are case-sensitive; padding and full payload validity are not checked.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
Alternative or Complementary methods
Use the complete codec matching the required alphabet and canonicality rules for real encoded data.
References
-
Calculation and input contract: decode/rfc4648-alphabet-symbol-index — tool.io
-
RFC 4648: Base-N encodings — RFC Editor
Similar or alternative tools
- Base91 Alphabet Symbol Index
Return one basE91 symbol's zero-based alphabet index.
- Decoding: Base64 Alphabet Symbol Value
Return a Base64 or Base64url symbol's value.