Developer Mock Data Generator
Generate ULIDs, ObjectIds, Nano IDs, order numbers, reserved test phone numbers, example.com emails and documented test card numbers.
How the Developer Test IDs works
Identifier formats follow their published specifications: ULIDs combine a 48-bit timestamp with 80 random bits in Crockford Base32, MongoDB ObjectIds use a 4-byte timestamp plus 8 random bytes, and Nano IDs draw 21 characters from a URL-safe alphabet.
Contact and payment values come only from ranges reserved for testing: example.com email domains (RFC 2606), 555-01xx US and Ofcom drama UK phone numbers, and card numbers published by payment providers for sandbox use. None can reach a real person or account.
How to use the Developer Test IDs in 3 steps
Step 1
Choose the type of mock data you need.
Step 2
Set how many rows to generate.
Step 3
Press Generate, then copy individual values or the whole list.
Frequently asked questions
Can I use these test card numbers to make real purchases?
No. They are publicly documented sandbox numbers that only work in payment provider test modes; live gateways decline them.
Which phone numbers are safe to use as fake data?
In the US, 555-0100 through 555-0199 are reserved for fictional use. In the UK, Ofcom reserves 07700 900000 to 07700 900999 for drama and testing.