Cloudflare Operations

Cloudflare Workers + Wrangler: runtime patterns, bindings, local dev, secrets, deploy, CI/CD, observability.

Ecosystem facts verified as of 2026-07.

Version context (verified 2026-07): Wrangler v4.x · config is wrangler.jsonc (Cloudflare's recommended format for new projects — some newer features are JSON-config-only; wrangler.toml still works and is widespread in older repos) · deploy command is wrangler deploy (the old wrangler publish is deprecated — see gotchas). Workers can now serve static assets, which is the current direction for full-stack and static sites over Pages (see Workers vs Pages).

Reference Files

File	Covers
references/bindings.md	Every binding (KV/D1/R2/DO/Queues/Hyperdrive/AI/Vectorize/Service/Analytics Engine) — config block, runtime API, when to reach for each, consistency model
references/workers-runtime.md	Runtime APIs, handlers (fetch/scheduled/queue/email/tail), CORS, caching, streaming, WebSockets, Durable Objects deep-dive, limits
references/workers-runtime-gotchas.md	Production footguns: detached fetch ("Illegal invocation"), per-colo caches vs KV vs D1, waitUntil semantics + outbox pattern, testing cron handlers, test-workerd lagging production, Email Service account states, Smart Placement, wrangler dev host rewriting
references/deploy-and-cicd.md	wrangler deploy, environments, secrets, Workers Builds, GitHub Actions + OIDC/API-token, gradual deployments, rollbacks, observability
assets/wrangler.jsonc.template	Commented, current wrangler.jsonc covering all common bindings + assets

Access / Zero Trust auth patterns (verifying Cf-Access-Jwt-Assertion, AUD tags, service auth, closed origins) → auth-ops skill, references/cloudflare-access.md.

Workers vs Pages Decision

Cloudflare added static-asset hosting to Workers; a single Worker now serves a static site, a full-stack app, or an API + SPA. For new projects, default to Workers with static assets. Pages still works and isn't deprecated, but Workers has the broader, faster-moving feature set (Durable Objects, Cron Triggers, Queues, richer observability) and is where Cloudflare's investment goes.

New project?
│
├─ Pure static site (no server logic)
│  └─ Workers + assets binding (asset-only — requests matching files never invoke Worker code, $0 for those).
│     Pages is also fine here; Workers keeps one platform if you later add logic.
│
├─ Full-stack / SPA + API / SSR framework (Next, Astro, Remix, SvelteKit, Hono)
│  └─ Workers + assets + a Worker script. Use the framework's Cloudflare adapter (C3: `npm create cloudflare@latest`).
│     This is the current recommended path — Pages' framework story is converging into Workers.
│
├─ Already on Pages and happy
│  └─ Stay. "What works in Pages works in Workers" — migrate only when you need a Workers-only
│     feature (DO, Cron, Queues, advanced observability). See the migrate-from-pages guide.
│
└─ Need Durable Objects / Cron Triggers / Queues / Tail Workers
   └─ Workers (these are Workers-only).

Asset serving modes (in the assets block): asset-only (no main) serves files directly and never bills Worker invocations for matches; assets + Worker serves matching files first, falls through to your fetch handler for everything else (or set run_worker_first to invoke the Worker before asset matching). Reach assets from code via env.ASSETS.fetch(request).

Wrangler Config Skeleton (jsonc)

Full annotated version: assets/wrangler.jsonc.template.

{
  "$schema": "node_modules/wrangler/config-schema.json",
  "name": "my-worker",
  "main": "src/index.ts",
  "compatibility_date": "2026-06-01",   // pins the runtime version — REQUIRED, bump deliberately
  "compatibility_flags": ["nodejs_compat"],  // opt-in runtime features (Node built-ins, etc.)

  "observability": { "enabled": true },  // turn on Workers Logs (off by default)

  "assets": { "directory": "./public", "binding": "ASSETS" },

  "kv_namespaces": [{ "binding": "CACHE", "id": "<kv-id>" }],
  "d1_databases": [{ "binding": "DB", "database_name": "app", "database_id": "<d1-id>" }],
  "r2_buckets":   [{ "binding": "BUCKET", "bucket_name": "uploads" }],

  "vars": { "ENVIRONMENT": "production" },  // NON-secret config only — never put secrets here

  "env": {
    "staging": { "vars": { "ENVIRONMENT": "staging" } }  // named env: deploy with --env staging
  }
}

• compatibility_date = yyyy-mm-dd, selects the runtime version. It's required and load-bearing: bumping it can change behaviour, so do it deliberately and test. compatibility_flags opt into upcoming/Node-compat features (e.g. nodejs_compat).
• Keep secrets OUT of vars — they land in plaintext in the deployed config. Use wrangler secret put / .dev.vars (secrets).
• TOML equivalent still parses; the binding shapes map 1:1 ([[kv_namespaces]], [[d1_databases]], …). New repos: prefer jsonc.

Bindings Table — When Each

Full config + runtime API for every binding: references/bindings.md.

Binding	Reach for it when…	Consistency / note
KV	Read-heavy config/cache, infrequent writes, global reads	Eventually consistent (~60s propagation). Fast reads, slow-ish writes. Not for "read your own write".
D1	Relational/SQL data, moderate scale, per-app database	SQLite at the edge. Strong within a DB; read replication is async. Use for app data with joins.
R2	Object/blob storage, large files, zero egress fees	S3-compatible. Replaces S3 for media/backups/assets you serve.
Durable Objects	Strong consistency, coordination, stateful realtime (chat, presence, game rooms, rate limit counters)	Single-threaded per object instance = serialized = consistent. The answer when KV's eventual consistency bites. SQLite-backed storage available.
Queues	Async/background work, decoupling, batching, retries	Producer binding + consumer Worker. Smooths spikes; guaranteed delivery with retries + DLQ.
Hyperdrive	Connecting to an existing external Postgres/MySQL with pooling + edge caching	Makes a regional DB feel fast from Workers. Needs nodejs_compat.
Workers AI	Run inference (LLM, embeddings, image) on Cloudflare's GPUs	ai binding → env.AI.run(model, ...). Pairs with Vectorize for RAG.
Vectorize	Vector DB for embeddings / semantic search / RAG	vectorize binding. Store + query embeddings, often fed by Workers AI.
Service bindings	Worker-to-Worker RPC without a network hop	Zero-latency internal calls; compose Workers as services.

Decision shortcut: need strong consistency or coordination → Durable Objects. Relational queries → D1. Big files → R2. Cheap global cache → KV. Background work → Queues. External SQL DB → Hyperdrive.

Minimal Worker

export default {
  async fetch(request, env, ctx) {
    const url = new URL(request.url);
    if (url.pathname === "/health") return Response.json({ ok: true });
    return new Response("Hello from the edge");
  },
};

env carries every binding (env.DB, env.CACHE, env.ASSETS, secrets, vars). ctx.waitUntil(promise) runs background work after the response is sent. Workers require ES module format (export default { fetch }) — the old service-worker addEventListener("fetch") format is legacy. Full handler patterns (scheduled/queue/email/tail, CORS, caching, WebSockets, DO): references/workers-runtime.md.

Local Dev & Secrets

npm create cloudflare@latest my-app   # C3 scaffolder — picks framework + adapter + wrangler.jsonc
wrangler dev                          # local dev server (Miniflare/workerd) on localhost:8787
wrangler dev --remote                 # run on Cloudflare's edge (real bindings) instead of local sim
wrangler types                        # generate TS types for env from your bindings → worker-configuration.d.ts

Secrets (never in vars):

Where	Mechanism
Local dev	.dev.vars file (dotenv format, gitignored) — wrangler dev loads it as env.*. Per-env: .dev.vars.staging.
Deployed	wrangler secret put NAME (prompts for value, encrypts it) · wrangler secret list · wrangler secret delete NAME
CI bulk	wrangler secret bulk secrets.json
Newer	Cloudflare Secrets Store bindings (account-level shared secrets) — see deploy reference

Add .dev.vars* to .gitignore. vars in config = plaintext public config; secrets are encrypted and write-only.

Deploy & CI/CD

Full detail: references/deploy-and-cicd.md.

wrangler deploy                  # build + upload + activate (NOT `wrangler publish` — deprecated)
wrangler deploy --env staging    # deploy a named environment
wrangler versions upload         # upload a new version WITHOUT making it live (gradual deploys)
wrangler versions deploy         # split traffic across versions (e.g. 10% new / 90% old)
wrangler rollback                # revert to the previous deployed version
wrangler tail                    # stream live logs from the deployed Worker

• Workers Builds — Cloudflare's native git-connected CI: push to GitHub/GitLab, Cloudflare builds + deploys. Zero-config for simple Workers; the default for most teams.
• GitHub Actions — cloudflare/wrangler-action. Authenticate with a scoped API token (CLOUDFLARE_API_TOKEN + CLOUDFLARE_ACCOUNT_ID as secrets), least-privilege (Workers Scripts:Edit). Template + workflow in the deploy reference.
• Gradual deployments — versions upload then versions deploy to shift a percentage of traffic; instant rollback if metrics regress.

Observability

• "observability": { "enabled": true } in config turns on Workers Logs (structured console.log capture in the dashboard) — off by default, opt in.
• wrangler tail for live request log streaming during an incident.
• Tail Workers — a Worker that receives execution traces of another Worker (centralised logging/alerting).
• Analytics Engine — write custom time-series metrics from a Worker (env.AE.writeDataPoint(...)), query via GraphQL/SQL API.

Common Gotchas

Runtime-level footguns that pass tests and ship — detached fetch ("Illegal invocation"), per-colo caches, waitUntil guarantees, cron testing, the test workerd lagging production, Email Service account states, Smart Placement, wrangler dev rewriting the request host — each with symptom/why/fix: references/workers-runtime-gotchas.md.

Gotcha	Detail	Fix
wrangler publish is gone	Renamed to wrangler deploy (Wrangler v3+). Old tutorials/CI still say publish.	Use wrangler deploy. Update any publish in scripts/CI.
wrangler.toml vs .jsonc	Both parse, but newer features are JSON-config-only and Cloudflare recommends jsonc for new projects.	New projects: wrangler.jsonc. Migrating: wrangler.toml → jsonc is a mechanical 1:1.
Missing compatibility_date	Required; absent or stale date silently pins old runtime behaviour.	Set it; bump deliberately and test — it can change semantics.
CPU time limit	Default 30s CPU per invocation (was 10ms/50ms historically; raised). Wall-clock can be longer while awaiting I/O. CPU-bound loops still get killed.	Offload heavy compute; use Queues for long async work; check the limits page for your plan.
Script size limit	3 MB (free) / 10 MB (paid) gzipped.	Trim deps, dynamic-import large modules, avoid bundling node-only libs.
KV eventual consistency	A write isn't globally visible for up to ~60s; not "read your own write".	Use Durable Objects when you need strong consistency.
Node built-ins fail	fs, crypto, etc. aren't there by default.	"compatibility_flags": ["nodejs_compat"] enables a polyfill subset; check what's actually supported.
Secrets in vars	vars ships plaintext in the deployed config.	wrangler secret put (deployed) / .dev.vars (local).
request/response body read twice	Streams are single-use.	request.clone() before the first read.
Bundling surprises	Wrangler uses esbuild; some packages assume Node/CommonJS.	Prefer Workers-compatible libs; set nodejs_compat; check the build output.

Setup

1. Install: npm install -g wrangler (or use npx wrangler / npm create cloudflare@latest to scaffold).
2. Auth: wrangler login (OAuth) for local; API token for CI.
3. Copy assets/wrangler.jsonc.template, strip the bindings you don't need, fill in IDs.
4. wrangler dev → wrangler deploy.

Staleness verifier

This skill encodes fast-moving facts (Wrangler major line, recommended compatibility_date, wrangler.jsonc config convention). scripts/check-cloudflare-facts.py guards them against silent drift:

# Structural (PR CI, no network): every catalogued fact's prose_token is still
# named in this skill's prose (incl. the jsonc template), and the currency
# note still carries a year.
python scripts/check-cloudflare-facts.py --offline        # exit 0 consistent, 10 drift

# Live (freshness job, never blocks a PR): wrangler still resolves on npm and
# its latest major matches the documented v4.x line.
python scripts/check-cloudflare-facts.py --live            # exit 10 major drift, 7 npm unreachable

The canonical fact set lives in assets/cloudflare-facts.json; when the Wrangler major, the recommended compatibility_date, or the config convention changes, update it to match or --offline fails CI.