About GenCore
A set of generators for test data — the kind that survives the checks real systems run. Free, no account, and nothing leaves your browser.
What GenCore is
GenCore is a collection of tools that produce realistic test data: phone numbers, addresses, names, card numbers, barcodes, QR codes, colours, credentials, crypto wallet addresses and more. Every generator follows the rules of the thing it imitates, so the output survives the validation your code, your database or your payment gateway will run on it.
It exists because filling a staging database with «test test test» tells you nothing, and because working out a valid EAN-13 check digit or an EIP-55 checksum by hand is nobody's idea of an afternoon. Pick a generator, take the output, move on.
What you can generate
Every tool runs in the browser and is free to use.
People, places and contacts
Secrets and identifiers
Payments and crypto
Codes and barcodes
Design and media
Who it is for
Developers
Seed a database, fill a form, exercise a validator, build a fixture file. Output in formats you can paste straight into code.
QA and testing
Edge cases on demand: a card number that passes Luhn, a phone number the library accepts, a barcode with the right check digit.
Analysts and designers
Plausible sample rows for a dashboard, a mockup or a demo, without borrowing anyone's real data.
Teaching and learning
See how a checksum, a BIP39 mnemonic or an HD derivation path actually works, by generating one and taking it apart.
Where your data goes
Nowhere. Every generator runs in your browser: numbers, keys and files are produced on your own machine and never sent to a server. No account, no upload, no stored history.
Which also means none of it belongs anywhere near real money, real identities or production systems. The data is structurally valid on purpose — it is still invented.
Frequently asked questions
Is GenCore free?
Yes, entirely. There is no account, no paid tier and no cap on how much you generate.
Is the generated data real?
No. It is built to satisfy the same rules as real data — check digits, checksums, country formats — but it belongs to no one and points at nothing. Never use it for real transactions or identities.
Are my files uploaded anywhere?
No. The image and video tools run entirely in the browser through WebAssembly. Your files never leave your device.
Can I use the output in production?
No. Everything here is for development, testing, demos and teaching. Production needs data issued by the real authority — a bank, a registrar, a carrier.
Pick a generator
Sixteen tools, no sign-up. Start with the one you came for.
Browse the tools