Behavior differences
Supported Worker API behavior is tracked against Workers runtime APIs. The differences below come from single-node topology and the pinned workerd. Cloudflare products that are not provided: Unsupported.
Workers
Section titled “Workers”| Topic | Behavior | Docs |
|---|---|---|
Outbound fetch / sockets / node:net |
Shared native workerd Network(allow=["public"]) |
TCP sockets |
Named Service/DO Fetcher.connect |
Declared capability tunnel, not a second general outbound | |
| CF IP-range block / self-connect detector / SMTP 25 | Not provided | |
| Runtime / binding-backend / workerd-internal listeners | Loopback | |
| Control / data listeners | Default loopback; an operator may expose them | |
| Exposed ingress and extra public-IP / SMTP egress policy | Operator-owned | |
| Request-scoped CPU / subrequest / simultaneous-connection quotas | The pinned workerd standalone process does not enforce them yet | Limits |
LimitEnforcer subrequest accounting |
No-op; getLimitsExceeded() always reports none |
|
Explicit Dynamic Worker limits |
Rejected natively, including an empty object; default CPU/memory/subrequest enforcement belongs to W2 | Bindings |
| Public-address boundary, product durable limits, handle cleanup, process supervision | Still apply | |
| Other numeric ceilings | Limits | |
| Deploy authority | One local SQLite authority and one supervised runtime generation | Versions and deployments |
| Global rollout / placement / traffic splitting / account management / billing control plane | Not provided | |
| Static Assets | Immutable deployment content on the selected Local/S3 authority; routing and bindings covered | Static Assets |
| Global CDN placement / replication / purge propagation / product quotas | Not provided | |
| Service Bindings | Default / named fetch and RPC within one platform authority | Bindings |
| Cross-region placement / global service discovery | Not provided | |
| Target admission, deployment pins, capability lifetime, recovery | Local and fail closed | |
| Cron | UTC only, five fields, plus documented local Quartz-like extensions | Cron Triggers |
| Cron recovery | At most the newest slot within misfire grace; no full downtime replay | |
| Cron known failures | Configured bounded local retry unless noRetry() is called |
Storage
Section titled “Storage”| Topic | Behavior | Docs |
|---|---|---|
| KV topology | Single-node SQLite authority; no global replication or edge-cache propagation timing | KV |
| R2 | Object bytes held by the selected single-node Local or S3-compatible authority | R2 |
| R2 global placement / replication | Not provided | |
| D1 topology | Single local-primary SQLite authority | D1 |
| D1 read-replica / region routing | Not provided | |
D1 served_by / region / colo metadata / billing counters |
Not provided | |
| D1 bookmarks | Opaque bookmarks preserve same-database local sequential visibility | |
D1 rows_read / rows_written |
Stable local SQLite execution counters | |
D1 dump() |
Current hosted non-alpha dump() is rejected |
Compute
Section titled “Compute”| Topic | Behavior | Docs |
|---|---|---|
| Durable Object placement | Placed on the single local workerd process | Durable Objects |
| Location hints / jurisdiction / global migration | No geographic scheduling effect | |
| Queues durability | Single-node scheduler.sqlite; at-least-once delivery |
Queues |
| Queues global FIFO | Not provided | |
| Queues unknown native dispatch | Retains lease and does not consume tenant retry budget; later delivery can repeat the same attempt number | |
| Workflows execution | Local SQLite authority | Workflows |
| Workflows callbacks | At-least-once until result commits; replay skips durably completed callbacks | |
| Workflows external effects | Do not roll back with Workflow snapshots | |
| Workflows cross-region execution / global placement / dashboard / observability | Not provided |
| Topic | Behavior | Docs |
|---|---|---|
| Cache authority | Workers Cache and Cache API are single-node local authority | Workers Cache, Cache API |
| Automatic caching | Requires explicit s-maxage or max-age |
|
| Heuristic TTL / global replication / purge propagation | Not provided | |
| Tiered cache / Cache Rules / Cache Deception Armor / plan-dependent behavior | Not provided | |
| Default object size | 16 MiB per cached object; 1 GiB logical body bytes per Worker | |
| Live values | ocd capabilities --json; see Limits |
|
| Images | Bounded local raster transform binding, not hosted Cloudflare Images | Images |
| Hosted delivery / upload / signing, URL transforms, video, AI upscale, product quotas | Out of scope |