Hhoppvia·1h agoHow to Build a Real-Time Taxi Booking and Dispatch SystemLearn how to build a real-time taxi booking and dispatch system, covering driver matching, GPS tracking, payments, backend architecture & scalability.9 min read·hoppvia.hashnode.dev
Aaleksejmenner·5h agoDesigning an Entitlement Model for Paid Telegram CommunitiesDesign paid Telegram access with entitlements, verified recipients, validity periods, refunds, and membership tracked separately.14 min read·alexmanner.hashnode.dev
DDmytro Nasyrov·10h agoCasino Wallet Recovery: Keep Session, Round and Ledger State SeparateA three-domain ownership map and fictional late-event sequence for assigning recovery evidence.17 min read·pharos-production.hashnode.dev
NNeeraj Sharma·10h agoSystem Design for a Private AI Video Studio: One GPU, Four Open Models and an Agent That DirectsA hosted AI video tool charges per credit and owns your workflow. A private studio on open models charges you per GPU minute and lets you keep your characters, prompts and outputs. We run one for our5 min read·axionry.hashnode.dev
DDigiCirq·11h agoWhatsApp Ticks Explained: One Grey, Two Grey, Two Blue, and Why Blue Doesn't Always Mean ReadOne tick is the server, two is the phone, blue is the eyes. How delivery and read receipts travel, why two grey ticks sit for days, how to read without blue.5 min read·digicirq.hashnode.dev1B
DDigiCirq·11h agoWhat Does “Rate Limited” Mean? (Twitter, Discord, APIs and the 429 Error Explained)Rate limited means you sent requests faster than the service allows, so it refused some. What the 429 error is, how token buckets count, and why apps do it.5 min read·digicirq.hashnode.dev
PParminder singh·1d agoPayment failed but money deducted: how idempotency keys stop double chargesThe app shows "Payment failed". A second later your phone gets an SMS: ₹2,000 debited. You tap Pay again. Now ₹4,000 is gone, and you still have no order. This post covers why this happens, the fixes5 min read·systemdesignwithparam.hashnode.dev1P
TTelcoEdge Inc.·23h agoBefore the Bill Exists: How Telecom Mediation Pipelines Turn Raw Usage Into Reliable DataUnderstand how telecom mediation systems ingest, normalize, validate, deduplicate, and process network usage records before they reach billing systems9 min read·telcoedgeinc.hashnode.dev
MMukul Kumar·1d agoStarlink's 2.5-Hour Global Outage: The Core Network Failed, Not the SatellitesAn analysis of Starlink's 2.5-hour global outage. How ground core control planes create single points of failure for LEO satellite networks.4 min read·buildopsy.hashnode.dev
RRONI DAS·1d agoHow Canada's new Real-Time Rail moves one payment, and what it teaches about backend designPayments Canada switched on a 24/7 system on 9 November 2026 that settles every payment between banks in real time. Here is how one payment travels, why the fraud checks come first, and why a bank asks before it retries.7 min read·systemdesignacademy.hashnode.dev
