Cloud infrastructure / AWS Lambda Event Functions alternative

AWS Lambda alternative for persistent agent workers

Lambda Event Functions execute event-driven handlers, with temporary runtime state and separate durable data services. Lambda now also offers distinct MicroVMs, Web Functions and Managed Instances products. This page focuses on event-function requirements and keeps those newer compute contracts separate.

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Reviewed 2026-10-19 · Published by the Sandbox0 team

When AWS Lambda Event Functions fits

Choose Lambda Event Functions for event integrations, short-lived handler execution and managed scaling. Durable Functions can coordinate multi-step work with checkpoints and waits; retain those workflow and event semantics when they are the central requirement.

When to consider Sandbox0

Consider Sandbox0 for a returning Linux worker with persistent system tools, complete RootFS growth and supported paused-file operations. You supply or retain event ingestion, retries, durable workflow semantics, scaling policies and observability.

Capabilities

AWS Lambda Event Functions and Sandbox0: what persists?

Feature comparison with documentation and verification status
Capability	AWS Lambda Event Functions	Sandbox0
Environment and runtime lifetime	AWS Lambda Event FunctionsStandard Event Functions have a 900-second timeout. Qualifying Managed Instances invocations can reach 5,400 seconds; MicroVMs are a separate product.View evidence ↗	Sandbox0ttl and hard_ttl default to 0 (disabled). Configure idle pause and deletion policies for the same persistent sandbox identity; an idle running sandbox still accrues compute charges.Read documentation →
Persistent files	AWS Lambda Event FunctionsWarm /tmp reuse is possible; durable data is stored through separately chosen services.View evidence ↗	Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFS	AWS Lambda Event FunctionsExecution environment reuse does not establish durable retention of complete writable system state.View evidence ↗	Sandbox0Persistence extends beyond /workspace to paths such as /usr/local, /etc, and /home. Runtime tmpfs and virtual filesystems are excluded.Read documentation →
Release compute, keep state	AWS Lambda Event FunctionsWorkflow waits/replay and initialized snapshots are different from arbitrary machine pause/resume.View evidence ↗	Sandbox0Pause compute between tasks; resume on available capacity. Default resume starts fresh processes from the saved filesystem.Read documentation →
Memory and process state	AWS Lambda Event FunctionsSnapStart captures initialization state, not a general live-agent RAM recovery contract.View evidence ↗	Sandbox0Experimental memory checkpoints can preserve compatible process state. Use memory: true on both pause and resume on a compatible deployment. A filesystem checkpoint alone does not preserve running processes.Read documentation →

Online RootFS growth

On growth-enabled images, Sandbox0 automatically expands the writable RootFS as free space runs low, within a configured sparse logical ceiling up to 64 TiB. Agent processes keep running. Growth is enabled in the qualified Cloud region; confirm activation for other regions. Existing images and snapshots retain their captured storage geometry. The ceiling is logical capacity, not preallocated host disk.

A larger /tmp allocation, a mounted external filesystem or durable workflow history does not provide automatic online growth of the full agent RootFS across function execution environments.

Files while compute is paused

Sandbox0's Files API reads persistent files without resuming compute. Filesystem-only pauses also permit edits; retained-memory pauses are read-only and reject mutations with 409. SSH, SFTP, file watching, and runtime-only mounts require running compute.

External object/database files can be accessed without invoking a function through their own services. That is distinct from a supported full-RootFS file interface for a paused function execution environment.

See paused file operations →

Warm reuse is not durable machine retention

Lambda may reuse an execution environment and its /tmp data for later invocations. Shutdown/replacement remains service-controlled, so warm files and background state are not a durable whole-machine contract. Store essential function results in an appropriate external data service.

Source 1 ↗

Ordinary invocation limits differ from newer compute products

The standard Event Function timeout is 900 seconds. Current quotas allow up to 5,400 seconds for qualifying Managed Instances asynchronous/event-source invocations, with stated exclusions. Lambda MicroVMs has its own interactive lifecycle; the 15-minute function limit should not be applied to that separate product.

Source 1 ↗

Durable operations and SnapStart preserve different state

Durable Functions record application steps/waits and recover with replay while skipping completed checkpoints. SnapStart snapshots initialized function state when publishing a version. Neither is a promise to retain an arbitrary returning agent’s complete live machine after each handler; additional operations, retention, caching or restore charges can apply.

Source 1 ↗

Pricing

Compare billing models, then price your workload

CPU allocation, memory, billing minimums, disk, plan fees, and supported workload differ. These meters are not equal-performance machine quotes. Confirm region, resource units, and included allowances before estimating a total.

AWS Lambda Event Functions

Pricing reviewed 2026-10-19

Event Function requests: $0.20 per million requests; Free allowance, request type/payload and effective regional terms apply.; Rate source ↗
x86 duration reference, US East N. Virginia: $0.0000166667 per GB-second; Published Event Function example; tiers, architecture and account terms can differ.; Rate source ↗
Event Function monthly free tier: 1M requests and 400,000 GB-seconds; Not a free MicroVM or provisioned-instance allowance.; Rate source ↗
Temporary /tmp allocation: 512 MB included; larger allocations metered; Configured ephemeral storage can range up to 10,240 MB; this is not durable RootFS storage.; Rate source ↗

Managed Instances, MicroVMs and Web Functions have different billing models. Durable operations/storage, SnapStart, provisioned concurrency, model use, network and external storage can add charges. A function example rate does not prove equal throughput or total-cost savings for a persistent machine.

Check current AWS Lambda Event Functions pricing ↗

Sandbox0

$0.015/GiB-hour compute (billed by the second at approximately $0.000004167/GiB-second), plus $0.02/GiB-month of retained incremental RootFS and memory checkpoint data. Shared base images and platform recovery retention are excluded; paused sandboxes accrue storage charges only.

Compute / GiB-hour: $0.015
Retained data / GiB-month: $0.02
Paused compute: $0.00

A 4 GiB agent, 100 running hours

$6.00 compute

4 GiB × 100 hours, billed by the second. Keeping 20 GiB of billable incremental data for a full billing month adds $0.40. CPU is derived from memory by the platform; choose a tier that fits your workload.

Understand storage billing →

Before migrating from AWS Lambda Event Functions

Inventory event sources, standard versus Managed Instances invocations, duration, warm-state assumptions, durable operations and external data.
Move compatible persistent worker logic to Sandbox0 while retaining event delivery, idempotency, retry and workflow controls explicitly.
Test installed tools, long tasks, growing files, paused operations and the combined runtime, event, durable-state, network and model bill.

Common questions

Is Sandbox0 a drop-in AWS Lambda Event Functions replacement?

Evaluate API compatibility and product scope. These products serve different core workflows, so a change may require a different architecture.

Does keeping files also keep a running agent?

Filesystem state and volatile process state are separate. Sandbox0 requires explicit compatible memory checkpoints to preserve running processes; its default filesystem resume starts fresh processes.

Sources and review scope

The Boat team's Battleships directory is the discovery source. References below describe the product and plan discussed on this page. Check current availability, regional terms and billing units before migrating. Where the cited material does not establish a capability or price, the comparison identifies that uncertainty.

Battleships research record ↗docs.aws.amazon.com/lambda/latest/dg/lambda-runtime-environment.html ↗docs.aws.amazon.com/lambda/latest/dg/gettingstarted-limits.html ↗aws.amazon.com/lambda/pricing/ ↗Sandbox0 RootFS capacity →

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