--- title: "Two Roads to Durable Agents: Replay vs. Snapshot — Eric Allam, Trigger.dev" url: https://daily.dev/posts/two-roads-to-durable-agents-replay-vs-snapshot-eric-allam-trigger-dev-2h2zopif0 source_url: https://www.youtube.com/watch?v=svCnShDvgQg type: video:youtube source: "AI Engineer" published: 2026-05-10T20:01:24.615Z updated: 2026-07-16T02:13:03.364Z tags: ["ai-agents", "llm"] reading_time: 16 upvotes: 0 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Two Roads to Durable Agents: Replay vs. Snapshot — Eric Allam, Trigger.dev **[AI Engineer](https://daily.dev/sources/aidotengineer)** · 16 min read · 0 upvotes · 0 comments ## Summary Eric Allam (Trigger.dev co-founder) explores two approaches to making AI agents durable in production: the replay model (caching side effects as steps in a journal) and the snapshot/restore model. He argues that replay, which underpins 30 years of stateless backend infrastructure, breaks down for long-running agents because the journal grows unboundedly. Instead, durable agents need two things: a persistent append-only context log (all LLM messages and tool calls) and execution-layer snapshots. Trigger.dev evolved from CRIU-based process checkpointing to Firecracker microVMs, achieving sub-second snapshots and ~200ms restores, compressing 512MB VM state down to ~14MB. They are open-sourcing this as a Docker-like CLI tool called FCRun, capable of 15,000 VM starts per minute. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Why Agent Crashes Are Nothing Like Database Crashes](https://daily.dev/posts/why-agent-crashes-are-nothing-like-database-crashes-ksqsnije3) · Daily Dose of Data Science \| Avi Chawla \| Substack · 2 upvotes · 0 comments - [Long-running Agents](https://daily.dev/posts/long-running-agents-irtro0veg) · Addy Osmani · 78 upvotes · 3 comments --- Tags: [#ai-agents](https://daily.dev/tags/ai-agents), [#llm](https://daily.dev/tags/llm) [View this post on daily.dev](https://daily.dev/posts/two-roads-to-durable-agents-replay-vs-snapshot-eric-allam-trigger-dev-2h2zopif0)