An approved R$ 100.00 refund, a provider that writes the transaction in 145 ms, and a caller that gives up after 3 seconds without seeing the response. In the first study of the Serverless Under Constraints series, I put Lambda with SQS and Lambda Durable Functions in front of the same ambiguous outcome, in a real AWS account and with an independent oracle: both variants refunded R$ 200.00, and both ended up reporting success.

The Lambda-or-not discussion usually ends on whoever defended their opinion with the most energy. Wardley Maps supplies the missing language: components that evolved into commodity get consumed as managed services, components that are your differentiator get built portable, and the real cost of lock-in grows toward your core. The instrument drawn on a real system, with a reading rule to decide before the architecture diagram.

What takes down your biggest sale of the year isn't total load, it's the hot key: one hot partition that throttles while the rest of the table sits idle. Space-based architecture fixes that by taking the database out of the critical path. On AWS serverless you inherit the principle, not the literal implementation, and most projects don't even need it.

The biggest mistake in serverless architecture isn't technical, it's organizational. Without Domain-Driven Design, you sell team autonomy and deliver the opposite: a distributed monolith dressed up as microservices.

Discover how AWS Lambda Durable Functions lets you create workflows that pause, wait for human approvals, and resume after hours - without paying for wait time.

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