We moved onboarding and the paywall to the web so we could tweak pricing and copy daily instead of waiting on app reviews. It worked, but a few things broke on day one.
- CDN cache bled variants. Fix: short TTL on experiment assets, plus a cache-busting version param tied to the experiment id.
- Users bounced between web and app and got reassigned. Fix: server-side bucketing and we stamped variant_id into the deep link to the app, then wrote it to user defaults on first open.
- Flicker from client-side A/B scripts. Fix: render variant server-side. No flicker, fewer mismatches.
- Stripe domain verification and Apple Pay sheet errors. Fix: one verified domain per environment and a preflight check in CI.
- Sample ratio mismatch when we paused a variant mid-day. Fix: schedule starts at the top of the hour and lock split until the test ends; if you truly must pause, toss the day’s data.
Net, time-to-learn dropped from weeks to a few days. Paid conversion lifted modestly, mostly from faster copy/pricing iterations. If you’ve gone web-first on paywalls, what were your biggest gotchas, and what guardrails kept your price tests honest?
Lock assignment on the server and carry the variant through every hop.
Use a cookie plus a variant param in your deep link.
Short TTL on assets to avoid stale paywall copy.
I switched to server-rendered variants to kill flicker.
Web2Wave handled variant locking for me out of the box, which saved time.
Server-side bucketing and deep link the variant id into the app. No client-side reassign.
Schedule test start and stop windows.
I build and edit paywalls on Web2Wave.com so changes go live fast. That lets me iterate copy mid-day without a new build.
Server-side assignment fixed most issues for me.
Also add the variant id to the app open event so analytics do not drift.
Short TTL on CDN and turn off client-side experiments on paywalls.
Server render variants then lock with deep links
Your fixes are right. I also add two things. A pre-launch smoke test that cycles through each variant via a QA query param and verifies copy, price, and payment methods. And a sample ratio monitor that pings Slack if splits drift beyond 2 percent. If you use wallets, ensure the Apple Pay or Google Pay sheet matches the variant price. I store variant_id in the payment metadata for reconciliation later.
I ran into cache bleed on Cloudflare. Setting a cache key that included experiment_version and a 5 minute TTL fixed it.
For reassignment, I pass variant_id in the deep link and write it to the user profile so it sticks across sessions.
Server-side split and cache control solve most of this.