What are the limitations of serverless architecture?

Serverless has significant limitations: (1) Cold start latency — 100ms–2s delays on first invocation, problematic for latency-sensitive applications; (2) Execution time limits — 15 minutes maximum for AWS Lambda; unsuitable for long-running tasks; (3) Statelessness — functions can't maintain in-memory state between invocations; requires external state stores; (4) Vendor lock-in — heavy use of platform-specific event sources and services makes migration to other clouds difficult; (5) Debugging complexity — distributed function invocations are harder to trace and debug than monolithic applications; (6) Concurrency limits — default limits can cause throttling during traffic spikes; (7) Cost at high scale — for consistently high traffic, EC2 Reserved Instances can be cheaper than Lambda; (8) Limited local development — reproducing the cloud environment locally is imperfect; (9) Package size limits — 250MB unzipped deployment package; (10) Hidden complexity — distributed nature moves complexity from infrastructure to orchestration (Step Functions, event choreography).