API & Caching
#3 My First Cloudflare KV Setup: Turning API Chaos into Cached Data
· Build Log
A first-principles KV rollout stabilized widget latency and reduced live-call failures.
Cloudflare KVstale fallbackcache continuity
1) TL;DR
- Live-only requests caused frequent empty-state incidents.
- KV introduced predictable read paths and continuity.
- UI now keeps last-known-good state when refresh fails.
2) What I Tried
I started with direct live fetches for most widget requests.
3) What Broke
Any upstream hiccup caused blank widgets or long user-visible waits.
4) Root Cause
There was no persistent cache layer and no stale-while-revalidate protection.
5) Before (Code Path)
worker/worker.js
- direct fetch in hot paths
- failure propagated as empty payload
frontend
- no last-success fallback
6) After (Code Path)
worker/worker.js
+ getCachedJson()/putCachedJson() helpers
+ stale fallback response branch
frontend
+ preserve previous state on refresh failure
7) Evidence (Git History)
- dfb779e fix(sigma-gamma): keep stale data visible.
- 8c73f47 fix(worker): preserve popup and stock discovery fallbacks.
- 1dd3fff fix(personal): preserve stock picks results during cache gaps.
8) What I Learned
Caching is a product reliability feature, not just an infrastructure optimization.
9) Frequently Asked Questions
Why show stale instead of error?
Continuity is better than blank dashboards for market monitoring workflows.
How is stale safety controlled?
By validity checks and refresh policy rather than unlimited TTL.
What was the biggest gain?
Consistent rendering under temporary API instability.