Cold Starts Are Dead
Lambda cold starts are no longer a significant issue for most workloads in 2026, with modern runtimes and optimizations like SnapStart and arm64 reducing initialization times dramatically. VPC-related cold start delays were resolved in 2019, and AWS's billing changes for the INIT phase have minimal real-world impact given cold starts occur in less than 1% of invocations. Benchmarks show P50 cold starts under 200ms for most runtimes, with some as low as 14ms on arm64. For the majority of applications, cold start latency is negligible compared to other components of request processing.
- ▪Modern Lambda cold starts in 2026 range from 50–400ms depending on runtime, with Rust and Go achieving sub-100ms on arm64.
- ▪VPC-related cold start penalties were eliminated in 2019 through Firecracker microVMs and eBPF-based network optimizations.
- ▪SnapStart reduces Java cold starts by up to 97% and is now available for Python, .NET, and Java on arm64.
- ▪AWS's 2025 billing change for the INIT phase affects most users minimally, as cold starts occur in less than 1% of invocations.
- ▪Real-world testing shows arm64 provides 17–25% faster cold starts across all runtimes compared to x86_64.
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try { if(localStorage) { let currentUser = localStorage.getItem('current_user'); if (currentUser) { currentUser = JSON.parse(currentUser); if (currentUser.id === 2745619) { document.getElementById('article-show-container').classList.add('current-user-is-article-author'); } } } } catch (e) { console.error(e); } Eric D Johnson for AWS Posted on Apr 29 • Originally published at edjgeek.com Cold Starts Are Dead #serverless #aws #lambda #coldstarts It never fails. Every time I talk about serverless, someone pushes back with the cold start argument. I still see it in forums, in blog comments, in architecture review meetings. "Sure, but what about cold starts?" I get it. Five or six years ago, that was a legitimate concern. But it's 2026. The data tells a different story.
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