Mock Jutsu: The Synthetic / Mock Test Data Generator Built for Banking and Fintech QA

Altan Sezer Ayan — Mon, 29 Jun 2026 22:13:21 GMT

After 12 years of QA work in digital banking and fintech, one problem never went away: realistic test data is hard to generate correctly. Most tools give you random strings. Banking systems need more than that — they need IBAN values that pass MOD-97 checksum, credit card numbers that clear Luhn validation, national IDs that match country-specific algorithms. One wrong digit and your test suite passes, but production rejects the data.

So I built Mock Jutsu — an open-source synthetic test data engine designed specifically for this problem.

What makes it different

Most fake data libraries generate plausible-looking strings. Mock Jutsu generates algorithmically correct values:

IBAN → MOD-97 checksum valid
Credit cards → Luhn algorithm valid
TCKN (Turkish ID) → Modulo 10/11 valid
BIC/SWIFT → ISO 9362 compliant
CUSIP, ISIN, SEDOL → correct check digits
National IDs for 45 countries → country-specific rules

Coverage: 395+ data types

Category	Examples
Banking	IBAN, BIC, SWIFT, routing numbers, sort codes
Cards	Luhn-valid card numbers, CVV, expiry, masked PAN
Identity TR	TCKN, YKN, VKN, MERSIS
Identity International	SSN, NIN, SIN, CPF, Aadhaar — 45 countries
Capital Markets	ISIN, CUSIP, SEDOL, LEI, FIGI, FIX messages
Crypto	Bitcoin, Ethereum, USDT addresses
Health	NHS number, ICD-10, HL7 FHIR
IoT	IMEI, MAC address, NMEA coordinates
E-commerce	Tracking numbers, barcodes, UBL invoices

Installation

pip install mock-jutsu

CLI usage

mockjutsu generate iban --locale TR
mockjutsu generate cardnum --locale US
mockjutsu generate tckn
mockjutsu generate iban --locale TR --mask
mockjutsu bulk tckn --count 100
mockjutsu template iban fullname cardnum --count 50 --locale TR
mockjutsu template iban fullname ssn --count 200 --format json

Python usage

from mockjutsu.core import jutsu

jutsu.generate("iban", locale="TR")
jutsu.generate("cardnum", locale="US")
jutsu.generate("tckn")
jutsu.generate("ssn")
jutsu.generate("cardnum", locale="US", mask=True)
jutsu.generate("iban", locale="DE", mask=True)

Compliance-safe masked output

PCI DSS, GDPR, and KVKK scenarios are covered with built-in masking:

jutsu.generate("cardnum", mask=True)   # ************3456
jutsu.generate("iban", mask=True)      # TR33******786457841326
jutsu.generate("tckn", mask=True)      # 348******54

Self-hosted REST API (Docker)

docker pull altansezerayan/mock-jutsu

docker run -p 8000:8000 altansezerayan/mock-jutsu

Then hit the API:

GET /generate/iban?locale=TR
GET /generate/cardnum?locale=US&mask=true
GET /bulk/tckn?count=100
POST /template  {"types":["iban","fullname","cardnum"],"count":5}

JMeter Plugin

Load testing with realistic banking data? The Mock Jutsu JMeter plugin generates data directly inside your JMeter test plans — no pre-generated files needed.

👉 mock-jutsu-jmeter on GitHub

Links

Resource	URL
Docs & HOW-TO (5 languages)	https://altansayan.github.io/mock-jutsu-api/
GitHub	https://github.com/altansayan/mock-jutsu-api
PyPI	https://pypi.org/project/mock-jutsu/
Docker Hub	https://hub.docker.com/r/altansezerayan/mock-jutsu
JMeter Plugin	https://github.com/altansayan/mock-jutsu-jmeter
Postman Collection	https://github.com/altansayan/mock-jutsu-api

What data types are you still hardcoding in your test environments? Happy to add them.

Tags: python, testing, fintech, opensource