The Cloudflare Field Manual

Part 1: Workers

1. Worker fetch to a hostname on your own zone fails with error 1042 2 min
2. A hand-rolled caches.default layer cached one error for 24 hours 2 min
3. A 150-line deploy: read live version id, probe /health, auto-rollback 3 min
4. An MCP server as one Pages Function: stateless Streamable HTTP 3 min
5. Start with one Worker and a router; split only when a boundary appears 2 min
6. compatibility_date is a runtime pin; bump it on purpose, alone 2 min
7. wrangler dev is local by default; opt bindings into remote one by one 2 min
8. Test a Worker inside workerd with the Vitest plugin, not in Node 3 min
9. Call a private Worker over a Service Binding: no URL, no latency 3 min
10. ctx.waitUntil buys thirty seconds after the response, not forever 2 min
11. Workers limits are CPU time, not wall time; waiting on fetch is free 3 min
12. Static assets from the Worker; run_worker_first decides who answers 3 min
13. Named environments inherit nothing that binds: vars, bindings, crons 3 min
14. Roll a version to 10% first: versions upload, then deploy with a split 3 min
15. CI deploys: scoped API token, wrangler pinned, migrations before code 3 min
16. Email at the edge: a send_email binding to send, email() to receive 3 min
17. caches.default is manual; Workers Caching is read-through with purge 3 min

Part 2: Workflows

1. WorkflowStep is an RPC receiver, so step.do.bind() throws 2 min
2. The 21-second production canary: pin, diff 82 bindings, roll back 3 min

Part 3: Queues & Crons

1. One */15 cron, many legs, each isolated in its own waitUntil 3 min
2. Our fail-closed cron gate was the outage: 11 silent days 3 min
3. One scheduled() handler serves every cron; controller.cron says which 3 min
4. A Queue consumer gets batches; ack per message, retry only failures 3 min
5. Queue work returns 202; the client polls a status row 3 min

Part 4: Observability

1. Cron dead-man's switch: heartbeat per tick, alert on the lower bound 2 min
2. Check provider balances on a cron; a card lapse killed runs for 24 h 3 min
3. Workers Logs is for last week; wrangler tail is for right now 3 min

Part 5: KV/R2/D1

1. wrangler kv/r2 (v4) targets the local simulator unless --remote 2 min
2. Pick the R2 public domain once; URLs get baked into content 2 min
3. Restic to R2 plus binlog shipping: a restore drill in 24 s, RPO 119 s 3 min
4. KV is a cache with sixty-second edges, not a database 3 min
5. Cache upstream JSON in KV with a TTL; serve stale when upstream fails 3 min
6. Upload to R2 through the Worker; presign a PUT for big files 3 min
7. Serve R2 objects with their own headers, ETag and Range support 2 min
8. D1: numbered migrations, prepare().bind(), batch() for atomicity 3 min
9. D1 read replicas: withSession() plus a bookmark across requests 2 min
10. Hyperdrive pools Postgres connections so Workers skip the handshake 3 min

Part 6: Zone

1. Make a Webflow page the homepage with a URL rewrite, not a Worker 2 min
2. Custom Domains make the Worker the origin; Routes put it in front 3 min

Part 7: Security

1. Kill switch as a Worker var: fail closed; spend ceilings: fail open 3 min
2. Mint scoped Cloudflare tokens from a master token; use, then delete 3 min
3. Credential-free edge companion: the customer pastes a Snippet 3 min
4. Put Cloudflare Access in front of a Worker, then verify its JWT too 3 min
5. Turnstile is only a widget until the Worker calls siteverify 2 min
6. The Rate Limiting binding counts per key inside the Worker 2 min
7. Declare required secrets; the deploy fails when one is missing 2 min

Part 8: Migrating from n8n

1. Compile n8n Code nodes mechanically; hash every node's parameters 3 min
2. Failover from n8n to a Workflow: three bindings, one executor per run 4 min

Part 9: Analytics Engine

1. Analytics Engine as cookie-less telemetry: blobs are positional 3 min

Part 10: Pages

1. Pages production branch isn't main: --branch main lands a preview 2 min
2. Pages _middleware.js: Accept text/markdown serves the .md sibling 2 min
3. New static site? Workers with static assets, not Pages 2 min
4. Pages Functions route by file path; _middleware.js wraps the rest 3 min

Part 11: AI

1. Workers AI: env.AI.run(model, input); stream text, send bytes 3 min
2. Put AI Gateway in front of every provider call: logs, cache, retries 3 min
3. Vectorize is the vector store; pair it with an embedding model 3 min

Part 12: Durable Objects

1. A Durable Object is one single-threaded instance per id, with SQLite 3 min
2. Hibernating WebSockets in a Durable Object: idle rooms cost nothing 3 min
3. Durable Object alarms are per-object timers; crons are global 2 min

Part 13: Getting Started

1. A Worker is a fetch handler plus bindings; Wrangler is the toolchain 3 min
2. Create, run locally and deploy a Worker in five commands 3 min
3. Vars, secrets and bindings all arrive on env; they are not the same 3 min