Sandbox comparison · Checked October 21, 2026
Agent37 vs Fly.io Sprites
Published running-cost comparison
96% less
$4.76 with Agent37 vs $120.09 with Fly.io Sprites
$115.33 less per sandbox per 730-hour month.
730 running hours at published rates, before credits and plan fees. Agent37: shared 2 vCPU, 4 GB RAM and 4 GB disk. Full CPU consumption where usage-billed; hardware, storage and session limits differ.
Sprites are persistent Linux computers for agents, with automatic wake, filesystem checkpoints and usage-based resources.
Lifecycle performance, side by side
Agent37 figures use our Performance dashboard telemetry from October 22, 2026 at 00:50 UTC to October 22, 2026 at 01:15 UTC, after the latest speed improvements. This is an early snapshot; small samples can vary. Fly.io Sprites figures are attributed to public benchmarks or vendor sources. Each cell states what was timed: API calls, host restores and first-command latency are different measurements, so this is not a normalized speed ranking.
| Operation | Agent37 | Fly.io Sprites |
|---|---|---|
| Create | 1.29 s median Measured · n = 37 Successful create API duration, from entering API authentication through the response. The sandbox has started; this does not wait for tenant application readiness or the first command. Mixed shapes, images, host regions and runtimes. | 1-2 s Provider-published timingFly's January 2026 Sprites launch article describes fresh VM creation in this range and shows a one-second CLI example. No sample count or percentile is supplied. |
| Resume / wake | 176 ms median Measured · n = 38 Host-timed restoration of a same-host gVisor memory checkpoint, including local startup housekeeping. Excludes the client round trip and subsequent command. Host reports are not filtered by workspace; cold boots and no-ops are excluded. | 100-500 ms warm Provider-published timingWarm wake retains memory and processes. A cold wake instead takes 1-2 s and starts processes fresh, according to Fly's lifecycle docs. |
| Sleep / suspend | Supported; timing not collected Auto-sleep can checkpoint memory. The current telemetry does not retain checkpoint duration. Stop timing below measures a different operation. | No numeric timing in reviewed sources. |
| Run a command | 461 ms median Measured · n = 811 Successful exec API duration, including the tenant command runtime. Commands vary across requests. This is not a controlled echo benchmark. Excluding host-reported command time: 338 ms median API/network overhead. | No numeric timing in reviewed sources. |
| Stop | 2.53 s median Measured · n = 2 Successful stop API duration. Stop discards memory state, preserves durable files and waits for the operation response. Includes requests to instances already stopped; this is not memory-preserving sleep latency. | No numeric timing in reviewed sources. |
| Restart | 1.26 s median Measured · n = 4 Successful restart API duration, including control-plane work and the restart operation. Mixed shapes, images, host regions and runtimes. | No numeric timing in reviewed sources. |
| Delete | 429 ms median Measured · n = 32 Successful delete API response duration. The response acknowledges deletion and ends billing; runtime stop, archive backup and physical teardown continue asynchronously. This is not time to completed cleanup. | No numeric timing in reviewed sources. |
Median is p50. Request counts are timing observations, not customers. Shapes, images and commands vary. Missing timing data does not mean a feature is unsupported.
Other Agent37 wake paths and measurement notes
Memory restore, VM
No observations in this window
n = 0. Host-timed restoration of a same-host VM memory checkpoint through the guest resume RPC and local housekeeping. Excludes the client round trip and subsequent command. Host reports are not filtered by workspace; cold boots and no-ops are excluded.
Wake by cold boot, default sandbox
No observations in this window
n = 0. Host-timed wake that cold-boots instead of restoring memory. Durable files remain, while live process state is not restored. Excludes the client round trip; host reports are not filtered by workspace.
Wake from cold storage
No observations in this window
n = 0. Control-plane-timed recovery of a sleeping instance from cold storage onto a host, including data recovery and boot. Process memory is not restored. Separate boundary from same-host memory restoration.
Wake after host relocation
No observations in this window
n = 0. Control-plane-timed wake that moves the sleeping instance to another host, including data transfer and boot. Process memory is not restored. Separate boundary from same-host memory restoration.
- This is an early production snapshot after the lifecycle performance rollout, not an SLA or a controlled comparison. The explicit window excludes traffic before the rollout. Shapes, image sizes, host regions and runtimes vary; low sample counts are less stable than a full-day sample.
- API metrics select successful 2xx responses, excluding the configured integration workspace and recognized automated-test workspace prefixes. API timers run from entering authentication through response creation, including downstream work but excluding the caller internet round trip.
- Exec includes arbitrary tenant command runtime. Exec overhead subtracts the host-reported command time; it is not equivalent to a full end-to-end command latency benchmark.
- Default and VM memory-restore timers run on the host. They exclude the client round trip and the subsequent application request or command. Host wake telemetry is not filtered by workspace. Counts are timing reports, not unique customers or guaranteed unique wake events.
- Cold boots, cold-storage recovery and host-relocation wakes have different paths from same-host memory restoration and are reported separately. Already-running wake no-ops are excluded.
- Start API timing is omitted because the aggregate includes already-running no-ops, which would make its median misleading as a resume or cold-start measurement.
- No sleep/checkpoint-duration aggregate is collected by the existing Performance helper. Stop is not a substitute for memory-preserving sleep.
- Observations are sorted and zero-based index floor(p * n) selects p50 and p90, with p = 0.5 and 0.9. The window includes its start and excludes its end. Counts represent operation observations, not customers. No observations is represented by null timing and zero samples, never zero latency or a carried-forward result.
- Only aggregate timings are published. No customer, workspace, instance, host, credential or raw-log data is included.
What 730 running hours cost
Reference workload: 2 vCPU and 4 GB RAM. USD list rates before credits, taxes and plan fees. This is aggregate runtime, not a promise of one uninterrupted session or equal hardware performance. GB and GiB follow each provider’s units. Full CPU consumption is assumed for usage-based CPU billing; idle-heavy workloads can cost less.
Agent37 Standard
$4.76
2 vCPU · 4 GB RAM · 4 GB persistent disk
Shared compute for bursty agent work. Sustained heavy CPU use may be limited on busy hosts. Choose Performance for reserved cores, at 4x standard compute.
Agent37 pricing and calculatorFly.io Sprites
$120.09
$0.0385/CPU-hour + $0.021875/GB-hour
Actual CPU and memory usage; assumes full selected resources throughout runtime. Storage extra: hot $0.000683/GB-hour, cold $0.000027/GB-hour. Lower utilization costs less.
Fly.io Sprites pricing source100-workspace cost estimate
$11,532.50 less per month.
$476.00 on Agent37 vs $12,008.50 on Fly.io Sprites.
Illustrative 100-workspace total at 730 running hours each, using the same rates and assumptions above. Totals use unrounded rates; volume discounts and account limits are not included.
Agent37 includes retained disk in this figure; competitor storage is excluded unless stated. Free allowances, minimum commitments, resource allocation, region and session limits can change your actual bill. Read the comparison method.
Why Agent37
Where Agent37 fits
Choose Agent37 for recurring agent work with a clear resource budget and ready-made harness templates. Keep the same disk between tasks, sleep when idle and pay low rates while the agent is working.
Start with a ready-made agent template or publish your own image. Keep files, expose apps and manage the machine through one API. Models and managed tools are optional and billed separately.
Requirements that could favor Fly.io Sprites
Sprites deserves a workload test when both CPU and memory use stay very low. Actual-use billing can beat an allocated-resource model for sparse jobs, and its credential-free connectors may satisfy a specific secrets-handling requirement.
For a persistent, bursty Linux agent without those requirements, Agent37 is our recommendation at the prices shown.
Beyond the hourly rate
| Factor | Agent37 | Fly.io Sprites |
|---|---|---|
| Persistence and lifetime | Keep the same instance and persistent data between tasks, with no fixed session deadline. Auto-sleep and stop reduce compute charges; retained disk still bills. | A persistent filesystem survives sleep. Checkpoints restore disk state, not running processes; hot and cold storage have separate rates. |
| Isolation and runtime | Standard sandboxes use gVisor. Choose a VM for its own Linux kernel and Docker support, at 2.5x standard compute. Standard and ordinary VM instances share host resources. | Hardware-isolated Linux VMs, documented by Fly.io. |
| Billing | Compute bills by the minute while awake, including CPU-idle time. Stopped or sleeping entry disk costs $0.36 per 730-hour month. No plan fee. | Actual CPU and memory usage; assumes full selected resources throughout runtime. Storage extra: hot $0.000683/GB-hour, cold $0.000027/GB-hour. Lower utilization costs less. |
Provider startup claims and our measurements use different boundaries. A resumed snapshot, a prewarmed session and a fresh machine are different operations. Compare all providers and timing sources.
Sources and verification
Checked October 21, 2026. Prices and features can change. Provider descriptions come from the official pages below; workload recommendations are our assessment.
Try your workload on Agent37.
Start your next agent on Agent37. Persistent files, your choice of agent and a standard sandbox from $4.76 per 730 running hours. Measure it against the latency and resource needs of your application.
Eligible new accounts. Add a card to unlock credit; no charge until you top up. Model and tool usage is separate.