Serverless ICYMI Q4 2025

This article summarizes major serverless announcements from AWS Q4 2025, highlighting innovations across Lambda, containers, APIs, and AI services.

• AWS Lambda durable functions enable multi-step workflows with automatic checkpointing and state management without external orchestration
• Lambda Managed Instances combine EC2 flexibility with serverless operations, supporting specialized hardware and cost optimization
• Lambda tenant isolation mode processes invocations in separate environments for secure multi-tenant SaaS applications
• Lambda now supports IPv6 networking, Rust GA, Python 3.14, Node.js 24, and Java 25 runtimes
• Lambda async invocations increased from 256 KB to 1 MB payload size
• Amazon ECS Express Mode simplifies containerized app deployment with single-command production-ready setup
• API Gateway adds response streaming for LLM applications and private ALB integration for VPC security
• EventBridge enhanced visual rule builder with drag-and-drop interface and event discovery
• Step Functions adds TestState API for local testing and new metrics dashboard
• DynamoDB supports multi-attribute composite keys in global secondary indexes
• Amazon Bedrock AgentCore includes quality evaluations and 18 new open-weight models
• S3 Vectors GA provides cost-optimized vector storage for AI and RAG at billion-vector scale

Q4 2025 delivered significant serverless innovations focused on state management, AI workflows, developer experience, and security across AWS compute services.