Show HN: CLI to order groceries via reverse-engineered REWE API (Haskell)

I just had the best time learning about the REWE (German supermarket chain) API, how they use mTLS and what the workflows are. Also `mitmproxy2swagger`[1] is a great tool to create OpenAPI spec automatically.

And then 2026 feels like the perfect time writing Haskell. The code is handwritten, but whenever I got stuck with the build system or was just not getting the types right, I could fall back to ask AI to unblock me. It was never that smooth before.

Finally the best side projects are the ones you actually use and this one will be used for all my future grocery shopping.

[1]https://github.com/alufers/mitmproxy2swagger

Show HN: CLI to order groceries via reverse-engineered REWE API (Haskell)
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Very cool! Thanks for sharing, I’ll try it out.

Haskell is indeed an interesting choice. ;)

this feels a bit like Sandra Bullock ordering pizza in „The Net“, impressive

Really cool to see things still being built in Haskell! How do you find using it compared to some of the newer languages that have more modern tooling?

Did you implement your own OAUTH2 flow in haskell for this?

I love the idea of a CLI for groceries. Do you have plans to support 're-order' scripts or meal-plan integration? I can imagine a workflow where a recipes.yaml file gets piped into your CLI to automatically fill the cart with everything needed for the week. Much faster than clicking through a mobile UI.