Caching

Part of the Sanchayam series. Why FX Matters Sanchayam tracks assets in their native currency. An Indian equity is priced in INR. A US stock is priced in USD. Crypto may be in USD or USDT. A bank account might be in AED. The portfolio view needs to aggregate everything into one base currency (the user’s choice - INR by default). Every portfolio snapshot, every holdings page, every P&L calculation requires converting across currencies. FX rates are fetched from the same Twelve Data API used for price feeds. A naive approach - one API call per currency per request - would be both slow and expensive. ...

Part of the MediaBridge series. Why Cache S3 at All S3 ListObjectsV2 is not free. Each call costs money, takes time, and returns at most 1,000 objects per page. A bucket with 10,000 files in a single prefix requires 10 paginated S3 calls just to render one folder. Do that on every page load and you burn money, slow the UI, and hit S3 rate limits under concurrent users. Presigned URL generation is also not free. It is CPU work on the server. A folder with 50 files requires 50 presigned PUT or GET URL generations per load if nothing is cached. ...