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

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21–30 of 94 posts

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

#24
I remember a friend and I in college were looking into ways to do this in the US but major grocery chains here are pretty sensitive about their product data being accessible by open APIs and web scraping...

It would have been a cool project!

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

#25
post #23

Surprised how little the B2C and even B2B e-commerce segment is providing API access for automation and agentic coding. One could easily set up rate limits, fraud detection and KYC checks upfront initial access.

B2B: Look at chefkoch.de They do use the REWE API, and I'm guessing not without their knowledge

B2C: Is it really surprising that a busines has no interest in providing more price transparency to their customers?

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

#26
post #12

Cool project, but have mixed feelings about publishing ever easier ways to access this API. They've locked down the API a while ago for a reason. Also there already exists this reverse engineered project: https://github.com/ByteSizedMarius/rewerse-engineering/ I do have a suggestion for your app though: Have it compare your basket of goods across different markets in your region to show you the cheapest option. I'm p…

>I do have a suggestion for your app though: Have it compare your basket of goods across different markets in your region to show you the cheapest option. I'd settle for just being able to sort items by unit price... I'm sure this is a [regulation-]solved problem in Germany though

> I'd settle for just being able to sort items by unit price

What do you mean? The official REWE app and website provide just that.

> I'm sure this is a [regulation-]solved problem in Germany though

Not sure what you mean by that.

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

#28
post #25
post #23

Surprised how little the B2C and even B2B e-commerce segment is providing API access for automation and agentic coding. One could easily set up rate limits, fraud detection and KYC checks upfront initial access.

B2B: Look at chefkoch.de They do use the REWE API, and I'm guessing not without their knowledge B2C: Is it really surprising that a busines has no interest in providing more price transparency to their customers?

When Amazon launches an API everyone cries. Same story over and over. Even better example: TakeAway-Group. The perfect MITM.

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

#29
I want to add something else to this. In the process of writing this, I also played with formal verification and formally verified the suggestion engine, which was a really nice side discovery.

The basic idea is to write a prove in Lean4 and then test both the production implementation (Haskell) and the Lean implementation against random inputs. Compare if the results are the same.

If that is the case -> you can be pretty sure the unproven production version is as correct as the proven lean version.

https://www.dev-log.me/formal_verification_in_any_language_f...

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

#30
post #12

Cool project, but have mixed feelings about publishing ever easier ways to access this API. They've locked down the API a while ago for a reason. Also there already exists this reverse engineered project: https://github.com/ByteSizedMarius/rewerse-engineering/ I do have a suggestion for your app though: Have it compare your basket of goods across different markets in your region to show you the cheapest option. I'm p…

The existing project was a great inspiration and helped me figure out the mTLS stuff. I totally get your mixed feelings, though.

I really like your suggestion. I will put it in an issue and look into that. https://github.com/yannick-cw/korb/issues/4

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