Cloudflare Workers for Platforms

Multi-tenant platform with isolated customer code execution at scale.

Use Cases

Multi-tenant SaaS running customer code
AI-generated code execution in secure sandboxes
Programmable platforms with isolated compute
Edge functions/serverless platforms
Website builders with static + dynamic content
Unlimited app deployment at scale

NOT for general Workers - only for Workers for Platforms architecture.

Quick Start

One-click deploy: Platform Starter Kit deploys complete WfP setup with dispatch namespace, dispatch worker, and user worker example.

Manual setup: See configuration.md for namespace creation and dispatch worker configuration.

Key Features

Unlimited Workers per namespace (no script limits)
Automatic tenant isolation
Custom CPU/subrequest limits per customer
Hostname routing (subdomains/vanity domains)
Egress/ingress control
Static assets support
Tags for bulk operations

Architecture

4 Components:

Dispatch Namespace - Container for unlimited customer Workers, automatic isolation (untrusted mode by default - no request.cf access, no shared cache)
Dynamic Dispatch Worker - Entry point, routes requests, enforces platform logic (auth, limits, validation)
User Workers - Customer code in isolated sandboxes, API-deployed, optional bindings (KV/D1/R2/DO)
Outbound Worker (optional) - Intercepts external fetch, controls egress, logs subrequests (blocks TCP socket connect() API)

Request Flow:

Request → Dispatch Worker → Determines user Worker → env.DISPATCHER.get("customer") 
→ User Worker executes (Outbound Worker for external fetch) → Response → Dispatch Worker → Client

Decision Trees

When to Use Workers for Platforms

Need to run code?
├─ Your code only → Regular Workers
├─ Customer/AI code → Workers for Platforms
└─ Untrusted code in sandbox → Workers for Platforms OR Sandbox API

Routing Strategy Selection

Hostname routing needed?
├─ Subdomains only (*.saas.com) → `*.saas.com/*` route + subdomain extraction
├─ Custom domains → `*/*` wildcard + Cloudflare for SaaS + KV/metadata routing
└─ Path-based (/customer/app) → Any route + path parsing

Isolation Mode Selection

Worker mode?
├─ Running customer code → Untrusted (default)
├─ Need request.cf geolocation → Trusted mode
├─ Internal platform, controlled code → Trusted mode with cache key prefixes
└─ Maximum isolation → Untrusted + unique resources per customer

In This Reference

File	Purpose	When to Read
configuration.md	Namespace setup, dispatch worker config	First-time setup, changing limits
api.md	User worker API, dispatch API, outbound worker	Deploying workers, SDK integration
patterns.md	Multi-tenancy, routing, egress control	Planning architecture, scaling
gotchas.md	Limits, isolation issues, best practices	Debugging, production prep

README.md