Segwit address validate

segwit-address-validate · version 1.0.0 · Encoding & checksums · free, no key needed

Validate a native segwit address and report which Bech32 or Bech32m rule failed.

Use when you need to: validate native segwit address · check segwit address checksum variant · check witness program length rules.

Decide before calling

Read the versioned contract and the supported scope below. Reuse segwit-address-validate@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 segwit-address-validate@1.0.0 for validate native segwit address. 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

• validate native segwit address
• check segwit address checksum variant
• check witness program length rules
• is this segwit address well formed
• detect mixed case segwit address
• check segwit address against expected hrp
• validate bech32m witness address

Not supported

• return the witness program bytes
• encode a new segwit address
• prove the program is a key or a payment hash
• repair an invalid checksum

Behavior

• expected_hrp must already be lowercase US-ASCII (code points 33..126 excluding 65..90). An uppercase expected_hrp such as BC is invalid_input with details.reason invalid_hrp and is not case-folded.
• A well-typed address inside the length limits returns {valid:false, reason} for a witness-rule failure and {valid:true, encoding, witness_version, program_length} for success. It does not return the program or the script pubkey.
• Version 0 requires Bech32 and a 20-byte or 32-byte program. Versions 1 through 16 require Bech32m and a 2-to-40-byte program. The other checksum constant yields reason wrong_encoding.
• Rule order for a verdict: character range, mixed case, separator, checksum, empty data, padding, program length, witness version, version-0 length, checksum variant, then exact HRP equality with expected_hrp.
• Wrong types, unknown fields, an empty address, a lone surrogate, and a non-lowercase expected_hrp throw invalid_input. Address length above 90, or expected_hrp length above 83, throws limit_exceeded before those rules. The address limit is checked first.
• Success does not mean the program is a hash, a public key, or a spendable output. The bytes are not inspected past the length rules.
• Disclaimer: format transform only; provides no confidentiality, integrity, or authenticity.

Input

• address (string, required): min length 1; max length 90
• expected_hrp (string, required): min length 1; max length 83; pattern ^[\x21-\x40\x5b-\x7e]+$

Output

• valid (boolean, required)
• reason (one of "mixed_case", "character_out_of_range", "no_separator", "empty_hrp", "too_short_checksum", "invalid_character", "bad_checksum", "empty_data", "invalid_padding", "invalid_program_length", "invalid_witness_version", "wrong_encoding", "hrp_mismatch", optional)
• encoding (one of "bech32", "bech32m", optional)
• witness_version (integer, optional): min 0; max 16
• program_length (integer, optional): min 2; max 40

Limits

• max address chars: 90
• max hrp chars: 83

Example

Request input:

{
  "address": "BC1SW50QGDZ25J",
  "expected_hrp": "bc"
}

Response:

{
  "result": {
    "valid": true,
    "encoding": "bech32m",
    "witness_version": 16,
    "program_length": 2
  }
}

How to call it

MCP

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

{
  "id": "segwit-address-validate",
  "version": "1.0.0",
  "input": {
    "address": "BC1SW50QGDZ25J",
    "expected_hrp": "bc"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/segwit-address-validate/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"address":"BC1SW50QGDZ25J","expected_hrp":"bc"}'

The machine-readable contract is at /v1/tools/segwit-address-validate/versions/1.0.0.

CLI

node cli.mjs run segwit-address-validate 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.
• Pem label validate: Check a PEM label against the RFC 7468 label grammar, without reading a payload.
• Segwit address encode: Encode a witness program as a native segwit address using Bech32 for v0 and Bech32m for v1-v16.
• Pem envelope validate: Check one RFC 7468 PEM envelope for labels, whitespace, and strict base64.
• Segwit address decode: Decode a native segwit address into witness version, program hex, and script pubkey.
• Bech32 decode: Decode Bech32 or Bech32m text into a lowercase HRP, 5-bit data, and the checksum variant.