A/B Testing vs. Feature Flags: They're Not the Same Tool
Feature flags and A/B tests share infrastructure but answer different questions. A guide to telling them apart before your rollout data lies to you.
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Insights on feature flags, progressive rollouts, and modern engineering practices from the ShipSilently team.
Export Your Feature Flags Before You Need To
Your flag configuration is production config that lives in exactly one place, on someone else's servers, with no backup. Here's a script that fixes that for LaunchDarkly in about four minutes, and what the export quietly leaves behind.
Read article →12 AI Prompts for Adding New Features to Your App (Without Breaking It)
A copy-paste prompt library for shipping real features with an AI coding agent, dark mode, search, notifications, onboarding, and more, plus the one habit that keeps a fast-moving feature from taking down production.
Read article →Your Feature Flag SDK Should Never Ask You to Restart Production
On July 10, LaunchDarkly's SDKs started 'giving up permanently' and the official remediation was to restart every affected application and Relay Proxy. That's not a recovery strategy, it's a design decision. Here's the design that makes restarts unnecessary, and how we built it.
Read article →How to Add a Command Palette (⌘K) to Your App
A build guide for adding a command palette to your product: the data model for commands, fuzzy search, keyboard navigation, accessibility, and shipping it to power users first.
Read article →How to Add Dark Mode to Your App the Right Way
A practical guide to adding dark mode: semantic color tokens, respecting OS preferences, avoiding the flash of wrong theme, and rolling it out to real users without a big-bang launch.
Read article →How to Add File Uploads to Your App the Safe Way
A practical guide to adding file uploads: presigned URLs, validation, virus and content-type checks, progress and resumability, and rolling the feature out without opening a security hole.
Read article →How to Add a Referral Program That Actually Drives Growth
A build guide for adding a referral program to your product: the data model, fraud-resistant attribution, reward mechanics, and how to test whether it moves the needle before rolling it out to everyone.
Read article →How to Add Passwordless (Magic Link) Login to Your App
A guide to adding magic-link and passwordless authentication: token design, expiry and single-use, rate limiting, the security tradeoffs, and migrating existing users without locking anyone out.
Read article →How to Add an AI Feature to Your Product Without Betting the Company on It
A pragmatic guide to shipping your first AI feature, scoping it, controlling cost and latency, handling the ways LLMs fail, and rolling it out so a bad response never becomes a bad quarter.
Read article →How to Add Undo to Any Destructive Action
A design and engineering guide to adding undo: the deferred-delete pattern that beats confirmation dialogs, soft deletes, undo stacks, and shipping it so users trust your product more.
Read article →How to Add In-App Notifications to Your SaaS
A complete guide to building an in-app notification system: the schema, unread counts that stay accurate, real-time delivery, user preferences, and how to launch it gradually instead of pinging everyone at once.
Read article →Not Everything Is a Feature Flag
A field guide to telling feature flags, config values, and user settings apart, three things that look identical at the API boundary and behave nothing alike. Miscategorize them and you end up with 240 'flags', a dashboard nobody trusts, and a 3am page about a setting that should have been a database row.
Read article →Yes, You Could Vibe-Code Your Own Feature Flag Service. Here's the Pitch Anyway.
deathbyclawd.com isn't wrong, Claude really can one-shot a feature flag service in an afternoon. The problem isn't the first afternoon. It's the next two hundred. A friendly, no-insults case for paying us a small amount of money instead.
Read article →The Mobile Feature Flag Problem: When Your Rollout Plan Has to Survive an App Store
On the web, a flag flip reaches every user in seconds. On mobile, your rollout has to survive review queues, offline devices, persistent on-disk state, and the user who hasn't updated since 2024. A different problem, a different set of patterns.
Read article →Feature Flags for AI: Why Model Swaps, Prompt Changes, and Tool Rollouts Each Need a Different Pattern
Standard percentage rollouts don't translate cleanly to LLM features. Sticky bucketing, shadow evaluation, and capability gating are the three patterns AI engineers actually need, and why your latency, cost, and eval signals all behave differently.
Read article →Kill Switches: How Feature Flags Become Your Three-Second Incident Response
Progressive rollouts let you ship slowly. Kill switches let you stop instantly. A practical guide to the on-call engineer's most underrated tool, and how to design your code so it actually works at 3am.
Read article →The 6 Levels of Feature Flag Maturity (And Why Most Startups Get Stuck at Level 3)
From cowboy push-to-prod to a real flag system, a brutally honest map of how engineering teams actually evolve their release strategy, and how to know which level you should be at.
Read article →Why Feature Flags Are the Secret to Shipping Faster
Feature flags split deployment from release. Here is what that buys a team that ships daily, and where the practice starts to cost you.
Read article →Edge Computing and Feature Flags: The Sub-Millisecond Advantage
How evaluating feature flags at the edge eliminates latency and transforms the performance profile of your application.
Read article →Trunk-Based Development with Feature Flags: A Practical Guide
How to adopt trunk-based development using feature flags to keep your main branch always deployable while shipping large features incrementally.
Read article →Progressive Rollouts: How to Ship Without the Big Bang
How to stage a rollout with feature flags, from a 1% canary through percentage releases, and what to watch at each step.
Read article →Managing Feature Flag Technical Debt
Feature flags improve velocity, but left unchecked they become a source of complexity. Learn how to keep your flag inventory clean and maintainable.
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