# AgentCell vs Fly.io for Tiny Always-On Apps

> Fly bills per second with auto-suspend — the closest PaaS to our economics. But ~$2/mo per always-on micro-VM adds up across twenty tools, the free tier is gone, and there's no identity layer.

Published: 2026-09-19  
Canonical: https://agentcell.dev/resources/vs-fly  
Markdown: https://agentcell.dev/resources/vs-fly.md

> **TL;DR verdict:** Use Fly.io when you want raw control — Machines, regions, any runtime, per-second billing. Use AgentCell when the workload is twenty mostly-idle tools shared with named people: Fly's ~$2/mo-per-app floor and DIY-auth shape tax exactly that sprawl.

## Where Fly.io wins (honestly)

- **Per-second billing with auto-suspend.** The closest any PaaS comes to our economics, and a genuine innovation for bursty workloads.
- **Control.** Firecracker microVMs, real regions, arbitrary runtimes — the most "real computer" of the simple PaaSs.
- **No seats, no tiers games.** Straightforward machine pricing engineers can reason about.

We respect Fly's model enough to have learned from it. The gaps are narrower here than anywhere else — and still structural.

## Gap 1: the $2/mo-per-app floor

A minimal always-on shared-cpu micro-VM runs roughly **$2/mo in compute, plus storage and IP** — and the free tier has been gone since 2024. Two dollars is nothing for one app. For twenty rarely-opened tools it is ~$40+/mo before anyone clicks anything, which quietly reintroduces the pruning instinct: "do we still need that one?" Once people prune, accumulation dies, and accumulation is the whole product. Idle cells on AgentCell sleep to zero and bill nothing for compute — the twentieth experiment costs nothing to keep.

(Also worth knowing: Fly's growth appears to have plateaued — ~$11.2M revenue in 2024 against Render/Railway's $100M 2026 raises. Directional, secondary-sourced, but relevant to "who will still be investing in this in 2028.")

## Gap 2: no identity or sharing layer

Fly gives you Machines and networking; who may open the app is entirely your code's problem. Same stitching as everywhere: an auth vendor, a second bill with enterprise floors, session logic duplicated across tools. And stopped Machines wake in multi-second times from cold — acceptable for services, awkward for "click this link in a meeting."

## Side-by-side

| | Fly.io | AgentCell |
|---|---|---|
| Billing | Per-second, auto-suspend; ~$2/mo always-on floor | Per-cell consumption, idle ~zero |
| Runtime control | Full — any image, real regions | Curated + org-customizable environments |
| Free tier | Removed 2024 | Free idle by design |
| Share with colleagues | DIY auth in every app | Share list + identity-aware front door |
| Wake from stopped | Multi-second | Wake-latency target measured pre-launch |
| Best for | Engineers wanting machine-level control | Teams wanting tools without operating machines |

## Fit checklist

**Use AgentCell when:** the audience is people with names, not services; idle cost across many tools must be ~zero; nobody wants to think about Machines.

**Stay on Fly when:** you need region placement, custom networking, or exotic runtimes; per-second billing already fits; auth is handled upstream.

## FAQ

**Is AgentCell cheaper than Fly for one busy app?**
Not necessarily — a single always-warm service may cost the same or less on Fly. The savings appear across *many idle* apps, which is the workload we're built for.

**Do you offer Fly-like region control?**
Data residency is a region choice in our design, not a thesis. Fine-grained region placement per cell is not a launch feature.

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*Running twenty Fly apps that mostly idle? [Deploy now](/docs/deploy/).*