Four free Cloudflare features, live

The free Workers plan quietly bundles things that used to cost money or a separate service. I wired four of them to live demos here (Durable Objects, Workers AI, Workers Logs, and custom trace spans), behind a tiny worker (cf-garage) routed at /garage/cf/*. The buttons hit real endpoints; nothing is faked. A fifth, Browser Rendering, I bound and deployed, then parked on the free tier's daily cap. Noted honestly below.

1 · Durable Objects: an atomic counter

A strongly-consistent, single-instance stateful object. The homepage's visitor counter uses KV, which is eventually-consistent and capped at 1,000 writes/day, so a busy day silently stalls it. A DO increments exactly once, no race, 100k writes/day. It used to cost money; it's free now, and it fixes that counter cleanly.

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env.COUNTER.get(id).fetch()  // SQLite-backed, atomic put

2 · Workers AI: caption a photo

Every model in the catalog, 10,000 neurons/day free. This runs @cf/llava-1.5-7b over a real grid photo to generate alt-text. A small, fast vision model hallucinates charmingly now and then (it once called a cloudy sky a UFO). One binding call does it: no GPU, no key.

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env.AI.run("@cf/llava-1.5-7b", { image, prompt })

3 · Workers Logs: structured observability

200,000 events/day, 3-day retention, free. Every button above emitted a structured log line from the worker ({ feature, ms, … }), filterable and searchable in the dashboard. I can't show it here (the logs live in Cloudflare, not the page), but it's on: [observability] enabled = true in wrangler.toml. Click around, then watch them stream in Workers & Pages → cf-garage → Logs.

console.log(JSON.stringify({ path, feature, ms }))

4 · Custom spans: trace a request

Workers auto-trace every platform call (each fetch, KV read, DO call) into a waterfall in Observability. As of Jun 16 2026 you can wrap your own logic in spans with ctx.tracing.enterSpan(), nested correctly. This endpoint runs a three-step pipeline (a Durable Object peek, a subrequest, and a compute loop), each in its own span with attributes. The canonical trace lands in Observability; the waterfall below is reconstructed live from the same span timings. (Run it twice: a cold Durable Object shows up as a fat first bar, then the warm path collapses to a few ms.)

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ctx.tracing.enterSpan("do.counter.peek", async (span) => { span.setAttribute("counter.value", n) })

The honest scorecard

All four ride the free Workers plan and work live above. Click them. They're shipped: a Durable Object increments with no race, Workers AI captions a real photo on a free GPU, every click leaves a structured log line, and a hand-instrumented request shows its own spans in the trace waterfall.

The fifth, parked honestly: Browser Rendering. Headless Chromium in a Worker (Puppeteer):

puppeteer.launch(env.BROWSER) → page.goto() →
      page.screenshot()

, the basis for on-the-fly og:image cards. I bind it and the worker deploys; no enable toggle exists (the binding is the access). The browser does provision. The catch was on my side: a timeout race that abandoned the in-flight browser stranded its websocket session (the free plan caps concurrency at 2), so each probe leaked a session and the next launch errored. The handler now bounds every launch and always releases the browser, and a bare hit no-ops instead of launching, so crawlers can't burn the 10 browser-minutes/day budget. It's unbuttoned here until the OG-image use case earns that budget; trigger it by hand at /garage/cf/screenshot?go=1.