Why 37signals Left the Cloud and What It Cost Them to Return
TL;DR
Here is a clear, practical guide to 37signals left the cloud: the fundamentals, the best practices that actually move the needle, common mistakes to avoid, concrete data points, and a short FAQ. Everything is structured so you can apply it to real projects today.
Key takeaways
- Treat Terraform state as production infrastructure: use remote state with locking, never edit it by hand, and keep modules small and versioned.
- Cloudflare Workers use V8 isolates rather than containers, which is why their cold starts are near-zero but they impose CPU-time and library constraints Lambda does not.
- Adopt FinOps early by tagging every resource, setting budgets and alerts, and making engineers see the cost of what they ship.
- Push latency-sensitive logic such as auth, redirects, personalization, and A/B routing to edge functions, and keep heavy stateful work in regional compute.
- Evaluate OpenTofu as a drop-in Terraform alternative if HashiCorp's BSL license or vendor lock-in is a concern for your organization.
This is a practical, up-to-date guide to 37signals Left the Cloud — what it is, why it matters in 2026, and how to apply it in real projects. It is written for developers and founders who want clear answers and proven best practices, not filler.
Whether you're just starting out or leveling up, treat this as a working reference you can return to. Every section is built to be skimmed, applied, and shared.
Edge computing and why location matters
Edge computing moves computation and data closer to where it is generated or consumed, instead of routing everything to a handful of centralized regions. For web applications this means running logic in points of presence spread across hundreds of cities, so a user in Mumbai or Sao Paulo hits nearby infrastructure rather than a distant data center. The payoff is lower round-trip latency, reduced backbone bandwidth, and the ability to filter or transform data before it travels upstream. Edge is not a replacement for regional cloud compute but a complementary tier: fast, stateless, geographically distributed logic in front of heavier centralized services. Use cases include content personalization, bot mitigation, image optimization, and IoT preprocessing where every millisecond and every byte counts.
Edge functions with Cloudflare Workers and peers
Cloudflare Workers is the best-known edge-functions platform, executing JavaScript, TypeScript, and WebAssembly in V8 isolates distributed across Cloudflare's global network. Because isolates start in roughly a millisecond and many can share a process, the platform delivers near-zero cold starts but constrains long-running CPU work and restricts some Node.js APIs. Complementary primitives such as Workers KV, Durable Objects, R2, and D1 provide edge-adjacent storage and coordination so functions are not purely stateless. Competing offerings include Deno Deploy, Fastly Compute, Vercel Edge Functions, and AWS Lambda@Edge, each with different runtime models and trade-offs. The general pattern is to run small, fast, latency-critical logic at the edge while delegating heavier or strongly consistent work to regional backends.
FinOps and controlling cloud spend
FinOps is the practice of bringing financial accountability to the variable, consumption-based spending of the cloud, so engineering, finance, and business teams share responsibility for cost. Codified by the Linux Foundation's FinOps Foundation, it follows a lifecycle of informing, optimizing, and operating, backed by cost allocation, forecasting, and rate optimization. Concrete tactics include tagging every resource for showback and chargeback, rightsizing over-provisioned instances, buying reserved capacity or savings plans for steady workloads, and deleting orphaned resources. Serverless helps by charging only for use, but it can also produce surprising bills at high volume, so it needs the same scrutiny. The cultural core of FinOps is making the cost of decisions visible to the engineers who make them, in near real time rather than at month-end.
Common pitfalls and best practices
Teams repeatedly stumble on a few predictable issues when adopting cloud, serverless, and edge. Ignoring cold starts on user-facing endpoints, editing Terraform state by hand, and leaving resources untagged all cause pain that is entirely avoidable with discipline. Vendor lock-in is real but usually worth accepting selectively, because chasing perfect portability sacrifices the managed services that justify the cloud in the first place. Good practice means designing stateless functions, keeping infrastructure declarative and reviewed in pull requests, setting cost budgets and alerts from day one, and respecting each platform's execution limits rather than fighting them. Observability with distributed tracing is essential because failures in distributed, ephemeral systems are hard to reproduce without it.
Multi-cloud versus hybrid cloud
Multi-cloud means deliberately using more than one public cloud provider, whether to avoid lock-in, meet data-residency rules, or pick the best service for each job. Hybrid cloud instead blends public cloud with private infrastructure such as on-premises data centers, often connected so workloads and data can move between them. The two are frequently conflated but solve different problems: multi-cloud is about breadth across vendors, hybrid is about spanning ownership boundaries. In practice most multi-cloud is workload-level rather than a single application running identically everywhere, because a true lowest-common-denominator abstraction sacrifices the managed services that make each cloud valuable. Tools like Kubernetes, Terraform, and service meshes reduce friction, but portability always carries an engineering and operational tax worth weighing honestly.
How serverless functions execute under the hood
In a function-as-a-service model like AWS Lambda or Google Cloud Run functions, you upload code and the provider handles provisioning, scaling, and patching the underlying compute. When a request or event arrives, the platform spins up an execution environment, loads your code, and runs the handler, keeping the environment warm for a while to serve subsequent invocations cheaply. You are billed only for actual execution time and memory, typically metered in fine-grained increments, so idle capacity costs nothing. Lambda and container-based services isolate workloads in lightweight microVMs such as AWS Firecracker, while Cloudflare Workers instead use V8 isolates that share a process. This architectural choice is precisely what drives the difference in startup latency, resource limits, and pricing between the two families of platforms.
37signals Left the Cloud: Key Facts and Data
According to recent industry research and the official documentation linked below:
- AWS Lambda, launched in 2014, is generally regarded as the service that popularized function-as-a-service, and by 2025 all three major hyperscalers plus Cloudflare and Vercel offered mature serverless compute platforms.
- Industry surveys such as the CNCF annual survey have consistently reported that a majority of organizations run some serverless workloads, with adoption highest for event-driven glue code, APIs, and background jobs rather than monolithic applications.
- V8 isolate-based platforms like Cloudflare Workers advertise cold starts on the order of single-digit milliseconds or effectively zero, versus the tens-to-hundreds of milliseconds typical for container- and VM-backed FaaS such as Lambda.
Quick-Reference Summary
A map of what this guide covers:
| Topic | What you'll learn |
|---|---|
| Edge computing and why location matters | Edge computing moves computation and data closer to where it is generated or consumed |
| Edge functions with Cloudflare Workers and peers | Cloudflare Workers is the best-known edge-functions platform |
| FinOps and controlling cloud spend | FinOps is the practice of bringing financial accountability to the variable |
| Common pitfalls and best practices | Teams repeatedly stumble on a few predictable issues when adopting cloud, serverless, and edge. |
| Multi-cloud versus hybrid cloud | Multi-cloud means deliberately using more than one public cloud provider |
| How serverless functions execute under the hood | In a function-as-a-service model like AWS Lambda or Google Cloud Run functions |
How to Get Started with 37signals Left the Cloud
A simple path that works:
- Learn the fundamentals of 37signals Left the Cloud from primary sources, not just tutorials.
- Build one small, real project end to end.
- Get feedback, refactor, and add tests.
- Ship it publicly and document what you learned.
- Repeat with a slightly harder project each time.
Build It with a World-Class Full Stack Developer
Sandeep Kumar Chaudhary is a full stack world-class developer. If you want to turn this into a real, production-ready product, get in touch — message directly on WhatsApp at +9779802348957 for a fast, no-pressure consult.
You can also explore the projects already shipped to thousands of users, or start a conversation here.
Final Thoughts
Treat Terraform state as production infrastructure: use remote state with locking, never edit it by hand, and keep modules small and versioned. The developers and teams who win in 2026 pair strong fundamentals with consistent shipping. Start small, stay curious, build in public, and revisit this guide as your skills grow.
Sources and Further Reading
Frequently Asked Questions
What is 37signals left the cloud?
Cloudflare Workers is the best-known edge-functions platform, executing JavaScript, TypeScript, and WebAssembly in V8 isolates distributed across Cloudflare's global network. Because isolates start in roughly a millisecond and many can share a process, the platform delivers near-zero cold starts but constrains long-running CPU work and restricts some Node.js APIs. This guide covers 37signals left the cloud end to end — core concepts, best practices, concrete data, and a step-by-step approach you can apply right away.
When should I use serverless containers instead of functions?
Choose serverless containers like Google Cloud Run or AWS Fargate when you need custom runtimes, existing container images, longer execution times, or more control than a rigid function packaging model allows. Functions are ideal for small, event-driven, short-lived tasks, while containers suit fuller applications that still benefit from scaling to zero. Both give pay-per-use economics without managing servers, so the deciding factors are packaging, duration, and portability.
What is the difference between serverless and edge computing?
Serverless is a billing and operational model where the provider manages scaling and you pay only for execution, and it usually runs in centralized cloud regions. Edge computing is about physical location, running code in many points of presence close to users. They overlap in edge functions like Cloudflare Workers, which are both serverless and geographically distributed, but you can have serverless without the edge and edge deployments that are not billed per invocation.
What is the difference between multi-cloud and hybrid cloud?
Multi-cloud means using two or more public cloud providers, often to avoid lock-in or to use each provider's strongest services. Hybrid cloud means combining public cloud with private or on-premises infrastructure, typically connected so workloads can span both. You can be multi-cloud without being hybrid and vice versa; they address vendor breadth and ownership boundaries respectively.
Why do serverless functions have cold starts?
A cold start happens when the platform has no warm execution environment ready and must create one, which involves fetching your code, booting the runtime, and running initialization before your handler executes. This adds latency the first time a function runs after being idle or when scaling to new instances. Isolate-based platforms like Cloudflare Workers minimize it because starting an isolate is far cheaper than booting a container or microVM.
Sandeep Kumar Chaudhary
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