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Going from CRUD backend to payments: things I wish someone told me
4 years back I was writing CRUD APIs for a food delivery startup. Then I joined a lending company, and in the first month I broke a reconciliation job, learned what a UTR is, and realised I did not know what a debit was. Writing this for anyone thinking about moving into fintech backend. Learn basic accounting before anything else. Not the full course. Just double entry, what assets and liabilities are, and why a…
rust: cannot borrow `*self` as mutable because it is also borrowed as immutable
making the pong game for @tomasz_k (long story) and im stuck on the borrow checker. i have a game struct with a list of entities and i want to update each one, but update needs to call a method on self struct Game { items: Vec<Entity>, score: u32, } impl Game { fn tick(&mut self) { for item in self.items.iter() { self.update(item); } } fn update(&mut self, item: &Entity) { // moves the item, maybe changes score } }…
RAG retrieve the correct chunk but model still answer wrong, why?
After fixing our retrieval (thanks for the help in my other post), now I see a different problem. In maybe 10% of the failed eval cases, the correct chunk IS in the context, I check it, but the model still answer wrong. Example: chunk say return window is 7 days for electronics and 30 days for clothes. Customer ask about headphones, bot say 30 days. Our context has 5 chunks, about 3000 tokens total, the correct one…
In ten days the clocks go back. Is your medication schedule ready?
On the last Sunday of October most of Europe goes back from summer time to standard time, and the hour from 02:00 to 03:00 happens twice. For most software this is a small annoyance. In a hospital it can mean a dose documented twice, or an infusion total calculated over the wrong number of hours. Siobhan wrote a very good story here some weeks ago about a renewal test that failed one night a year. This is the…
Daily sales report across timezones: which day does an order at 11:30pm Bangkok belong to?
We store created_at as timestamptz. Until now all markets were UTC+8 (Singapore, Malaysia) so we just did: select (created_at at time zone 'Asia/Singapore')::date as day, sum(amount) from orders group by 1; Now we add Thailand (UTC+7). Order at 23:30 Bangkok time is 00:30 next day in Singapore. Thai team want it in their day, regional report want one number per day. Options: convert each order using its market…
hit £1,000 MRR today. some honest context because these posts usually skip it
£1,042 MRR as of this morning. 31 paying groomers, 1 in ireland, 2 in the netherlands (VAT sorted, thanks to this site honestly). im very happy and also want to put some context next to the number, because "£1k MRR!!" posts always skip the boring bits. its not a salary after stripe fees, SMS costs (around £140 a month now), hosting, my accountant and the domain i keep forgetting to renew, i take home roughly £700 a…
How do you run discovery interviews when customers only want to talk about bugs?
I'm running discovery for a new scheduling feature, and every interview turns into a support session within five minutes. Customers have a list of bugs and complaints, and they've been waiting for someone to listen. I don't want to shut them down, because the frustration is real and hearing it builds trust. But I end up with 40 minutes of bug reports and 5 minutes about the problem I'm actually trying to understand.…