Best of Serverless — April 2026

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   Article

   ByteByteGo·6w

   EP210: Monolithic vs Microservices vs Serverless

   A curated system design newsletter covering five topics: a comparison of monolithic, microservices, and serverless architectures with practical tradeoffs; CLI vs MCP for AI agents across six dimensions including token cost, auth, and governance; a comparison of five major coding agents in 2026; an overview of essential AWS services and where they fit in production stacks; and a beginner-friendly visual explanation of JWT structure and security.

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2. 2
   Article

   Modal·6w

   Butter is joining Modal

   Modal has acquired Butter, a San Francisco-based AI sandbox technology startup. Butter founder Erik Dunteman and researcher Raymond Tana will join the Modal Sandbox team. The Butter team brings expertise in agent harness engineering, computer-use agents, deterministic memory systems, and codegen. Their most recent project, bVisor, is a virtual Linux kernel built in Zig for lightweight, ephemeral sandboxes. The acquisition aims to make Modal Sandboxes a best-in-class product.

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3. 3
   Article

   AWS Fundamentals·5w

   AWS S3 Files vs EFS — Cost Comparison, POSIX Limits, and Lambda Setup

   AWS S3 Files is a managed POSIX/NFS file system backed by S3 storage, offering up to 13x lower storage costs than EFS ($0.023/GB vs $0.30/GB) for large-file workloads. The post covers how S3 Files works (file system, mount target, access point), the full cost comparison including edge cases where S3 Files is actually more expensive (small files under 1 MiB), the critical 60-second write-back delay that breaks coordination patterns, POSIX limitations (no hard links, no cross-client file locking, non-atomic directory renames), and a step-by-step AWS SAM setup for Lambda including VPC networking, service role, and file system provisioning. A decision table helps choose between S3 Files and EFS based on file size, consistency needs, and concurrency requirements.

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