Put a UUID on the invoice before you need it
The claim Give every business record a stable, public-safe identifier at the moment it is created, separate from its database primary key. The auto-incrementing integer is fine ins...
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Engineering
Engineering notes, infrastructure deep dives and practical guides from the Exotecho team.
Offset pagination lies to you after page fifty
The claim LIMIT 20 OFFSET 5000 has two defects, and the well-known one is the lesser. Yes, it gets slower linearly, because the database must produce and discard five thousand rows...
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Every feature flag needs a deletion date
The claim A feature flag is a deployment tool with a lifespan measured in weeks. A flag that survives past its launch becomes permanent configuration nobody understands, and a code...
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Every timeout must be shorter than the one in front
The claim Most cascading outages are not caused by a component failing. They are caused by a component being slow while every timeout in the stack is longer than the one upstream o...
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Structured logs with a request ID, or none at all
The claim Free-text log lines without a correlation identifier are not diagnostic data. They are a diary. During an incident you cannot answer the only question that matters — what...
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Never send email from inside a web request
The claim Any call to a third-party service inside a request handler makes that service a hard dependency of your application. Sending mail synchronously means your order confirmat...
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Images, not JavaScript, are what your pages weigh
The claim On a typical content or commerce site, images account for the majority of transferred bytes — usually 55% to 75% — and the fix is a build step you configure once, not a f...
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Ship every schema change as two deploys
The claim A migration that changes the shape of a table and the code that reads it in the same deploy cannot be rolled back. During the seconds or minutes when old and new applicat...
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Your health check should touch the database
The claim An endpoint that returns 200 unconditionally is worse than having no health check at all. It converts a loud failure into a silent one: your load balancer keeps routing t...
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