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DERKONLINE

The Journal

Notes from the build.

Field notes from an AI-native studio on performance, security, deliverability, infrastructure, and the craft of shipping software that stays up. Written by the people who build it.

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Stacks of coins rising from left to right on a warm neutral backgroundProduct & Business

How To Cut Your Cloud Bill In Half Without Breaking Anything

The handful of changes that recover most wasted cloud spend, ranked by savings against the risk of touching them.

8 min read
Blue fiber-optic strands radiating outward from a single point against a dark backgroundNetworking

Serve Unlimited Subdomains From One Cloudflare Origin Certificate

Use a wildcard SAN origin cert behind Cloudflare so every new subdomain goes live without minting or renewing a certificate.

7 min read
A row of dark server racks with cabling receding down a data-center aisleInfrastructure

Why Safari Gets 520 Errors When Chrome Works on Your Nginx Server

Large auth cookies plus nginx HTTP/2 field-size defaults silently reset Safari streams; here is the two-line fix.

7 min read
Glowing blue and teal fiber-optic strand tips with soft bokeh on a dark backgroundNetworking

Why Your Site Returns 520 in Safari but Works in Chrome

Safari coalesces cookies into one HPACK field that trips nginx 1.18 limits, so Cloudflare returns an untraceable 520. Two lines fix it.

7 min read
Glowing blue fiber-optic strands forming a dense connected network on a dark backgroundNetworking

Expose an Internal App Publicly Without Opening a Single Port

Cloudflare Tunnel reaches out from your server instead of letting the world reach in, so your origin IP and firewall stay invisible.

7 min read
Clean data center corridor lined with dark server racks and a polished floorInfrastructure

Self-Hosting vs Managed Cloud: The True Cost Founders Miss

A clear-eyed model of when running your own servers wins on margin and control, and when managed infrastructure is the cheaper bet.

7 min read
Dense teal fiber patch panel with neatly bundled network cablesInfrastructure

The Safari Only 520 Error That Large Auth Cookies Quietly Cause

How Safari-coalesced cookies overflow nginx HPACK limits behind Cloudflare, and the two-line server block that ends the 520 mystery.

7 min read
Teal fiber optic cables flowing from a network switch in a dark rackProduct & Business

The Bandwidth Bill Quietly Eating Your Margin and How to Cap It

Egress and cache misses scale with growth in ways founders never model; here is where the spend hides and how to claw it back.

7 min read

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Journal · DERKONLINE