Bech32 decode

bech32-decode · version 1.0.0 · Encoding & checksums · free, no key needed

Decode Bech32 or Bech32m text into a lowercase HRP, 5-bit data, and the checksum variant.

Use when you need to: decode bech32 or bech32m text into hrp and symbols · tell bech32 apart from bech32m by checksum · lowercase a bech32 string after checking its checksum.

Decide before calling

Read the versioned contract and the supported scope below. Reuse bech32-decode@1.0.0 when your input, required output and limits match it. Choose another approach for an unsupported operation.

Explain the choice

"I can use bech32-decode@1.0.0 for decode bech32 or bech32m text into hrp and symbols. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

Supported

• decode bech32 or bech32m text into hrp and symbols
• tell bech32 apart from bech32m by checksum
• lowercase a bech32 string after checking its checksum
• read five-bit data from a bech32 string
• reject mixed case bech32 text
• parse a bech32m checksummed string
• split bech32 text on the final separator
• recover the hrp from an uppercase bech32 string

Not supported

• create a new bech32 checksum
• convert 8-bit bytes to 5-bit symbols
• enforce segwit program length or witness version
• locate which character was mistyped

Behavior

• Accepts a single-case string of at most 90 characters. All-uppercase and all-lowercase are both accepted. Mixed ASCII case is rejected before the checksum, then the string is returned in lowercase.
• The separator is the last character 1. The HRP before it must be 1 to 83 characters of ASCII 33-126. The body must be charset characters qpzry9x8gf2tvdw0s3jn54khce6mua7l with at least 6 checksum characters.
• The checksum selects the variant. Polymod residue 1 is bech32 (BIP 173). Polymod residue 0x2bc830a3 is bech32m (BIP 350). Any other residue is a bad checksum. data omits those 6 symbols.
• Format failures throw invalid_input. A string longer than 90 characters throws limit_exceeded before charset or checksum work. No witness-version policy is applied.
• Disclaimer: format transform only; provides no confidentiality, integrity, or authenticity.

Input

• text (string, required): min length 8; max length 90; pattern ^[\x21-\x7e]+$

Output

• hrp (string, required): min length 1; max length 83; pattern ^[\x21-\x40\x5b-\x7e]+$
• data (array of integer, required): max items 82; each min 0; each max 31
• variant (one of "bech32", "bech32m", required)
• text (string, required): min length 8; max length 90; pattern ^[\x21-\x40\x5b-\x7e]+$

Limits

• max text chars: 90

Example

Request input:

{
  "text": "A12UEL5L"
}

Response:

{
  "result": {
    "hrp": "a",
    "data": [],
    "variant": "bech32",
    "text": "a12uel5l"
  }
}

How to call it

MCP

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

{
  "id": "bech32-decode",
  "version": "1.0.0",
  "input": {
    "text": "A12UEL5L"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/bech32-decode/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"text":"A12UEL5L"}'

The machine-readable contract is at /v1/tools/bech32-decode/versions/1.0.0.

CLI

node cli.mjs run bech32-decode 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Bech32 validate: Check Bech32 or Bech32m text and return a reason, without throwing when the checksum fails.
• Bech32 encode: Encode lowercase HRP and 5-bit data as Bech32 or Bech32m text using that checksum.
• Bech32 convert bits: Regroup integers between bit widths using BIP 173 rules, rejecting bad leftover padding.
• Pem envelope parse: Parse one RFC 7468 textual envelope into its label and lowercase hex bytes.
• Segwit address decode: Decode a native segwit address into witness version, program hex, and script pubkey.
• Asn1 oid parse: Parse an X.680 object identifier value into numeric arcs and dotted form.