Lei validate

lei-validate · version 1.0.0 · Identifiers & check digits · free, no key needed

Validate a 20-character LEI's ISO/IEC 7064 MOD 97-10 check digits and parse its LOU prefix and entity part.

Use when you need to: validate a legal entity identifier · check lei check digits · is this lei number valid.

Decide before calling

Read the versioned contract and the supported scope below. Reuse lei-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 lei-validate@1.0.0 for validate a legal entity identifier. 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 a legal entity identifier
• check lei check digits
• is this lei number valid
• lei checksum validator
• parse lei lou prefix and entity part
• verify iso 17442 identifier
• does this lei pass mod 97

Not supported

• looking up which entity an LEI actually identifies (no GLEIF lookup)
• checking an LEI is currently active, lapsed or duplicated in the GLEIF database
• validating a bare Modulus 97-10 string with no LEI structure (see checkdigit-validate)

Behavior

• lei must be exactly 20 characters: no case folding, no trimming. Any other length is reason wrong_length, checked first.
• lou_prefix (characters 1-4), entity_part (5-18) and check_digits (19-20) are the raw positional substrings whenever lei is exactly 20 characters, regardless of charset or check-digit validity; all three are null only when length already failed.
• Characters 1-18 must each be a digit or an uppercase letter; characters 19-20 must each be a digit, else reason invalid_character.
• Check: expand all 20 characters to decimal digits (A=10...Z=35), concatenate, and take the remainder modulo 97 one digit at a time; the LEI is valid only when the remainder equals 1 (the ISO/IEC 7064 MOD 97-10 self-check property). Any other remainder is reason check_digit_mismatch.
• valid is true only when length, charset and the MOD 97-10 remainder all pass, in that order; only one reason is ever returned.

Input

• lei (string, required): min length 1; max length 20

Output

• valid (boolean, required)
• reason (one of null, "wrong_length", "invalid_character", "check_digit_mismatch", required)
• lou_prefix (string or null, required): min length 4; max length 4
• entity_part (string or null, required): min length 14; max length 14
• check_digits (string or null, required): min length 2; max length 2

Limits

• max lei bytes: 20

Example

Request input:

{
  "lei": "HWUPKR0MPOU8FGXBT394"
}

Response:

{
  "result": {
    "valid": true,
    "reason": null,
    "lou_prefix": "HWUP",
    "entity_part": "KR0MPOU8FGXBT3",
    "check_digits": "94"
  }
}

How to call it

MCP

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

{
  "id": "lei-validate",
  "version": "1.0.0",
  "input": {
    "lei": "HWUPKR0MPOU8FGXBT394"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/lei-validate/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"lei":"HWUPKR0MPOU8FGXBT394"}'

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

CLI

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

Get the client at /clients/cli/.

Related tools

• Checkdigit validate: Validate a full value's trailing check digit(s) against a named algorithm (Luhn, Verhoeff, Damm, ISO 7064, GS1, mod 10).
• Isin validate: Validate a 12-character ISIN's ISO 6166 Luhn check digit and parse its country prefix, NSIN and NSIN scheme.
• Cas number validate: Validate a CAS Registry Number's position-weighted mod 10 check digit over its variable-length first segment.
• Figi validate: Validate a 12-character FIGI's structure, forbidden-prefix rule and Modulus 10 Double Add Double check digit.
• Iccid validate: Validate a 19/20-digit ICCID's Luhn check digit, require the 89 major industry id, split issuer/account digits.
• Imo number validate: Validate a 7-digit IMO ship identification number's weighted mod-10 check digit, with or without the 'IMO ' prefix.