The original title is 12 words: "We read the source of 16 sandbox SDKs before writing ours"

Short summary

A team building the createos-sandbox SDK read the source code of 16 competitor SDKs (E2B, Daytona, Modal, Cloudflare, CodeSandbox, Vercel, and others) to extract design patterns and avoid their mistakes. They adopted stateful handles, method-aware retry policies with exponential backoff and jitter, and a 10-class typed error hierarchy with structured metadata, while rejecting gRPC, OpenAPI codegen, and WebSocket layers as unnecessary complexity. The result is a zero-runtime-dependency, hand-written fetch client where each module stays under 300 lines, designed to be readable by both humans and increasingly by LLMs generating code.

• •Surveyed 16 sandbox SDK source codes to extract design patterns and avoid common pitfalls
• •Implemented method-aware retries, typed error hierarchy, and zero runtime dependencies
• •Rejected gRPC, OpenAPI codegen, and WebSocket layers in favor of a readable hand-written REST client

Generated with AI, which can make mistakes.