How PayPal Scales Payments: The Architecture of Global Trust

<blockquote> <p>The pager went off at 2:14 AM.</p> </blockquote> <p>If you’ve spent any time operating distributed systems, you know that sound. It doesn’t just wake you up; it

<p>Most Shopify middleware works fine in staging. It breaks in production, during a sale, at 11pm on a Friday.</p> <p>After auditing dozens of integrations, the failures are

<p>Our quiz app has two paid plans. Changing between them used to be three steps in this order:</p> <ol> <li>Cancel the customer's current subscription.</li> <li>Open a Stripe

<p><em>Three API calls. One template ID that has to carry through all of them.</em></p> <p>Resend's API for sending a templated email is three steps:</p> <ol> <li>Create a

<p>I review a lot of webhook handlers. Roughly <strong>3 out of 5 either have a subtle signature-verification bug</strong> — or someone disabled verification entirely "to make it

<p>Most applications don't fail because of bad code.</p> <p>They fail because of bad architecture decisions made early that nobody questioned <br /> until it was too late.</p>

<p>You've heard of DevOps. You've heard of AIOps. You've probably heard of MLOps.</p> <p>But there's a category that doesn't exist yet — and it's the one the AI industry needs

<p>An inference server stopped generating tokens while more than 200 GiB of host memory remained available. Its health endpoint kept returning HTTP 200. The first visible