Two Roads to Durable Agents: Replay vs. Snapshot — Eric Allam, CEO, Trigger.dev
May 10, 2026 · 16:36
Eric Allam, CEO of Trigger.dev, argues that durable agents require two separate strategies: context durability via an append-only log of LLM interactions, and execution durability via OS-level snapshot and restore. He contrasts this with the replay model, which wraps every step in a journal but becomes unwieldy as agents run for hours. Trigger.dev built snapshot-and-restore on Firecracker microVMs, achieving snapshots as small as 14 MB compressed with sub-second save and hundred-millisecond restore times. The approach preserves files, memory, and subprocesses that a journal cannot capture. Allam notes that IBM mainframes in 1966 pioneered checkpointing, and that Trigger.dev will open-source the tool as FCRun.
