# Rf creditor reference validate

`rf-creditor-reference-validate` · version 1.0.0 · Identifiers & check digits · free, no key needed

Validate an RF Creditor Reference's ISO 11649 shape and MOD 97-10 check digits, and parse its base reference.

**Use when you need to: validate an rf creditor reference · check an iso 11649 structured reference · is this rf payment reference correct.**

## Decide before calling

Read the [versioned contract](/v1/tools/rf-creditor-reference-validate/versions/1.0.0) and the supported scope below. Reuse `rf-creditor-reference-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 `rf-creditor-reference-validate@1.0.0` for validate an rf creditor reference. 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 an rf creditor reference
- check an iso 11649 structured reference
- is this rf payment reference correct
- verify a structured creditor reference for a sepa invoice
- confirm a remittance reference before reconciling a payment
- בדיקת תקינות מספר אסמכתא מובנה לתשלום

## Not supported

- computing a new RF reference from a base reference (use rf-creditor-reference-compute)
- Swiss QR-bill references (use swiss-qr-reference-validate)
- IBAN or BIC validation

## Behavior

- electronic = reference with every ASCII space removed, then every ASCII a-z upper-cased to A-Z (no other case folding, no locale). print = electronic split into groups of 4 Unicode code points (so a surrogate pair is never split) joined by a single space. Both are always returned.
- shape_ok = electronic matches ^RF[0-9]{2}[A-Z0-9]{1,21}$ (literal 'RF', 2 decimal check digits, 1-21 alphanumeric base-reference characters). If not shape_ok, valid:false, reason:'invalid_character', check_digits:null, base_reference:null.
- Otherwise check_digits = electronic[2:4] (as found, not recomputed) and base_reference = electronic[4:].
- MOD 97-10 check: rearranged = base_reference + 'RF' + check_digits (the literal letters R, F, never a country code). digits = alnum_to_digits(rearranged). If digits mod 97 != 1, valid:false, reason:'check_digits_mismatch'. Otherwise valid:true, reason:null. Pure string parsing and MOD 97 arithmetic; no pinned dataset.

## Input

- `reference` (string, required): min length 1; max length 34

## Output

- `valid` (boolean, required)
- `reason` (one of null, "invalid_character", "check_digits_mismatch", required)
- `check_digits` (string or null, required): pattern `^[0-9]{2}$`
- `base_reference` (string or null, required): min length 1; max length 21
- `electronic` (string, required): min length 1; max length 34
- `print` (string, required): min length 1; max length 42

## Limits

- max reference bytes: 34

## Example

Request input:

```json
{
  "reference": "RF18 5390 0754 7034"
}
```

Response:

```json
{
  "result": {
    "electronic": "RF18539007547034",
    "print": "RF18 5390 0754 7034",
    "valid": true,
    "reason": null,
    "check_digits": "18",
    "base_reference": "539007547034"
  }
}
```

## How to call it

### MCP

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

```json
{
  "id": "rf-creditor-reference-validate",
  "version": "1.0.0",
  "input": {
    "reference": "RF18 5390 0754 7034"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/rf-creditor-reference-validate/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"reference":"RF18 5390 0754 7034"}'
```

The machine-readable contract is at [/v1/tools/rf-creditor-reference-validate/versions/1.0.0](/v1/tools/rf-creditor-reference-validate/versions/1.0.0).

### CLI

```sh
node cli.mjs run rf-creditor-reference-validate 1.0.0 --input input.json --base-url https://computefirst.net
```

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

## Related tools

- [Rf creditor reference compute](/tools/rf-creditor-reference-compute): Compute the MOD 97-10 check digits and full ISO 11649 RF Creditor Reference for a base reference (invoice number).
- [Swiss qr reference validate](/tools/swiss-qr-reference-validate): Validate a 27-digit Swiss QR-bill QR reference's modulo-10-recursive check digit and reject all-zero references.
- [Checkdigit validate](/tools/checkdigit-validate): Validate a full value's trailing check digit(s) against a named algorithm (Luhn, Verhoeff, Damm, ISO 7064, GS1, mod 10).
- [Iso6346 container validate](/tools/iso6346-container-validate): Validate an 11-character ISO 6346 container number's mod-11 check digit and split the owner code, category and serial.
- [Iban validate](/tools/iban-validate): Validate an IBAN's country, registry length, BBAN structure and MOD 97-10 check digits, and parse its bank/branch code.
- [Imo number validate](/tools/imo-number-validate): Validate a 7-digit IMO ship identification number's weighted mod-10 check digit, with or without the 'IMO ' prefix.