# Bech32 encode

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

Encode lowercase HRP and 5-bit data as Bech32 or Bech32m text using that checksum.

**Use when you need to: encode lowercase hrp and five-bit symbols as bech32 · bech32m checksum text from an hrp and symbol list · create bech32 text with checksum constant one.**

## Decide before calling

Read the [versioned contract](/v1/tools/bech32-encode/versions/1.0.0) and the supported scope below. Reuse `bech32-encode@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-encode@1.0.0` for encode lowercase hrp and five-bit symbols as bech32. 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

- encode lowercase hrp and five-bit symbols as bech32
- bech32m checksum text from an hrp and symbol list
- create bech32 text with checksum constant one
- create bech32m text with checksum constant 2bc830a3
- attach a six character bech32 checksum
- hrp and data symbols to lowercase bech32
- bech32 encode an empty data part
- build a bech32m string from values 0 to 31

## Not supported

- decode a bech32 string back into symbols
- choose bech32 or bech32m from a witness version
- correct a damaged checksum
- encode bytes with RFC 4648 base32

## Behavior

- HRP is 1 to 83 characters, each ASCII 33-126, and must already be lowercase. A-Z is rejected. The encoder does not case-fold.
- data is 5-bit integers 0 through 31. There is no default variant: pass bech32 (checksum constant 1, BIP 173) or bech32m (checksum constant 0x2bc830a3, BIP 350).
- Output text is lowercase HRP, separator 1, data characters, and a 6-character checksum. The same HRP and data produce different checksums for the two variants.
- The encoded character count is HRP length + data length + 7 and must be at most 90. A longer combination is limit_exceeded before symbols are scanned.
- This is a generic codec. It does not apply segwit witness-version policy, program-length rules, or error correction.
- Disclaimer: format transform only; provides no confidentiality, integrity, or authenticity.

## Input

- `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)

## Output

- `text` (string, required): min length 8; max length 90; pattern `^[\x21-\x40\x5b-\x7e]+$`
- `variant` (one of "bech32", "bech32m", required)
- `checksum` (string, required): min length 6; max length 6; pattern `^[qpzry9x8gf2tvdw0s3jn54khce6mua7l]{6}$`

## Limits

- max hrp chars: 83
- max data items: 82
- max character count: 90

## Example

Request input:

```json
{
  "hrp": "a",
  "data": [],
  "variant": "bech32"
}
```

Response:

```json
{
  "result": {
    "text": "a12uel5l",
    "variant": "bech32",
    "checksum": "2uel5l"
  }
}
```

## How to call it

### MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "bech32-encode",
  "version": "1.0.0",
  "input": {
    "hrp": "a",
    "data": [],
    "variant": "bech32"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/bech32-encode/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"hrp":"a","data":[],"variant":"bech32"}'
```

The machine-readable contract is at [/v1/tools/bech32-encode/versions/1.0.0](/v1/tools/bech32-encode/versions/1.0.0).

### CLI

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

Get the client at [/clients/cli/](/clients/cli/).

## Related tools

- [Bech32 decode](/tools/bech32-decode): Decode Bech32 or Bech32m text into a lowercase HRP, 5-bit data, and the checksum variant.
- [Bech32 validate](/tools/bech32-validate): Check Bech32 or Bech32m text and return a reason, without throwing when the checksum fails.
- [Bech32 convert bits](/tools/bech32-convert-bits): Regroup integers between bit widths using BIP 173 rules, rejecting bad leftover padding.
- [Segwit address encode](/tools/segwit-address-encode): Encode a witness program as a native segwit address using Bech32 for v0 and Bech32m for v1-v16.
- [Pem envelope format](/tools/pem-envelope-format): Format a label and lowercase hex bytes as a canonical RFC 7468 PEM envelope.
- [Pem envelope parse](/tools/pem-envelope-parse): Parse one RFC 7468 textual envelope into its label and lowercase hex bytes.