PromptDev
Generate mock data from a schema
A prompt for generating realistic mock data from a schema, edge rows included: unicode names, boundary dates, nulls where allowed.
Last updated
Fill in the blanks
Assembled in your browser — nothing you type is stored or sent anywhere.
Your prompt
Generate 20 rows of realistic mock data for this schema, as JSON array.
Make the data look real, not obviously synthetic: varied names including non-ASCII and unicode ones, realistic-looking but fake emails and IDs, dates spanning a believable range. Include a few edge-case rows on purpose: a boundary date (today, far past, far future — wherever the field allows it), a null or empty value in every field that's nullable, and a name with an apostrophe, accent, or non-Latin script to catch encoding bugs. Never put a null in a field the schema marks required. If the schema doesn't say whether a field is required or nullable, ask instead of guessing.
Schema:
[paste the table or schema definition here]
Model-agnostic — works in Claude, ChatGPT, Gemini or any AI chat.
Why this prompt works
- →Explicitly requiring unicode names and boundary dates targets exactly the edge cases synthetic data usually skips, which is where a real system's validation or encoding bugs hide.
- →Forbidding a null in a required field stops the model from generating a fixture set that would fail the very schema it was built from the moment you loaded it.
- →Asking about unclear nullability instead of guessing prevents the dataset from silently encoding a wrong assumption about your schema that later gets mistaken for real data.