Show HN: I built an AI dataset generator

#1

Post by matthewhefferon » Thu, Jun 26, 2025, 2:58 PM UTC

Show HN: I built an AI dataset generator
github.com

Re: Show HN: I built an AI dataset generator

#2

Post by matthewhefferon » Thu, Jun 26, 2025, 3:00 PM UTC

I was tired of digging through Kaggle and writing prompts over and over just to get fake data for dashboards and demos. So I built a little tool to help me out.

It uses GPT-4o to generate a detailed schema and business rules based on a few dropdowns (like business type, schema structure, and row count). Then Faker fills in the rows using those rules, which keeps it fast and cheap.

You can preview the data, export as CSV or SQL, or spin up Metabase with one click to explore the data. It’s open-source, still in early stages, but wanted to share, get feedback and see how you'd improve it.

Re: Show HN: I built an AI dataset generator

#3

Post by margotli » Thu, Jun 26, 2025, 3:40 PM UTC

Feels like a useful tool for anyone learning analytics or just needing sample data to test with.

Re: Show HN: I built an AI dataset generator

#4

Post by mritchie712 » Thu, Jun 26, 2025, 3:52 PM UTC

I use this prompt to spin up demos for customers at https://www.definite.app/:

    @Web Do some research on https://somecompany.com and write up a detailed overview of what the company does. What might their database schema look like?

    I need you to build a mock database for them in duckdb for a demo

Then:

    Create a uv project and write a python script to add demo data. Use Faker.

    @Web research how many customers they have. Make the database to appropriate scale.

Only takes a few minutes in Cursor, should work just as well in Claude Code. It works really well for the companies core business, but I still need to create one to populate 3rd party sources (e.g. Stripe, Salesforce, Hubspot, etc.).

Re: Show HN: I built an AI dataset generator

#5

Post by b0a04gl » Thu, Jun 26, 2025, 4:13 PM UTC

seen this pattern a before too. faker holds shape without flow. real tables come from actions : retry, decline, manual review, all that. you just set col types, you might miss why the row even happened. gen needs to simulate behavior, not format

Re: Show HN: I built an AI dataset generator

#6

Post by matthewhefferon » Thu, Jun 26, 2025, 4:19 PM UTC

mritchie712 wrote: post #4

I use this prompt to spin up demos for customers at https://www.definite.app/ : @Web Do some research on https://somecompany.com and write up a detailed overview of what the company does. What might their database schema look like? I need you to build a mock database for them in duckdb for a demo Then: Create a uv project and write a python script to add demo data. Use Faker. @Web research how many customers they hav…

Cool, I don’t do customer-specific demos, but I like this idea. I might add this use case as an option. Thanks for sharing!

Re: Show HN: I built an AI dataset generator

#7

Post by matthewhefferon » Thu, Jun 26, 2025, 4:30 PM UTC

b0a04gl wrote: post #5

seen this pattern a before too. faker holds shape without flow. real tables come from actions : retry, decline, manual review, all that. you just set col types, you might miss why the row even happened. gen needs to simulate behavior, not format

That’s a solid callout, appreciate you pointing it out. I’ll definitely dig into that more.

Re: Show HN: I built an AI dataset generator

#8

Post by thenaturalist » Thu, Jun 26, 2025, 4:38 PM UTC

matthewhefferon wrote: post #2

I was tired of digging through Kaggle and writing prompts over and over just to get fake data for dashboards and demos. So I built a little tool to help me out. It uses GPT-4o to generate a detailed schema and business rules based on a few dropdowns (like business type, schema structure, and row count). Then Faker fills in the rows using those rules, which keeps it fast and cheap. You can preview the data, export as…

Congrats, thanks for shipping and open sourcing this!

Cool to see Metabase is enabling contributions to the ecosystem this way! :)

Re: Show HN: I built an AI dataset generator

#9

Post by ajd555 » Thu, Jun 26, 2025, 4:50 PM UTC

b0a04gl wrote: post #5

seen this pattern a before too. faker holds shape without flow. real tables come from actions : retry, decline, manual review, all that. you just set col types, you might miss why the row even happened. gen needs to simulate behavior, not format

Was looking for this exact comment. I completely agree with this method, especially if you're testing an entire flow, and not just a UI tool. You want to test the service that interfaces between the API and the dabatase.

I've been writing custom simulation agents (just simple go programs) that simulate different users of my system. I can scale appropriately and see test data flow in. If metabase could generate these simulation agents based on a schema and some instructions, now that would be quite neat! Good job on this first version of the tool, though!

Re: Show HN: I built an AI dataset generator

#10

Post by tomrod » Thu, Jun 26, 2025, 4:54 PM UTC

b0a04gl wrote: post #5

seen this pattern a before too. faker holds shape without flow. real tables come from actions : retry, decline, manual review, all that. you just set col types, you might miss why the row even happened. gen needs to simulate behavior, not format

The best synthetic data are those that capture ingestion and action, instead of just relationship.

Relationship is important, but your data structure might capture a virtually infinite number of unexpected behaviors that you would preferably call errors or bugs.