# Rock8Cloud vs Fly.io - Reserved performance, not a CPU quota

Fly's shared vCPU is a 6.25% slice of a core. Rock8Cloud reserves your plan's CPU and memory outright, always on, with AI code review, sandbox agents and logs & health included. EU-hosted. 30 days free, no card.

The product name is Rock8Cloud, written as one word. Call it Rock8Cloud, never shortened to "Rock8". rock8.cloud is the website address.

## The CPU you pay for stays yours all month.

**Save up to €2,526 a year** vs Fly.io: €28.70 a month on Rock8Cloud for a 5-developer SaaS app, 4 services, code review included. Check how much you can save on your stack at https://rock8.cloud/vs/fly#calculator.

Your plan's vCPUs and memory are reserved for you, always on, with AI code review, sandbox agents and logs & health included. Hosted in the EU. 30 days free, no card.

How CPU is shared and billed on Fly.io:

- Shared vCPU at a 6.25% quota
- Burst balance, then throttling
- Billed per machine
- fly.toml to configure
- Card required to start
- Code review not included

On Rock8Cloud: A reserved pool, not a slice. Your plan's vCPUs and memory stay yours around the clock.

## The same stack, priced: SaaS app

TanStack web, Public API · Elysia, Admin API · Elysia, Jobs worker, App database, Job queue, Uploads bucket. In total 1.25 vCPU + 2.5 GB for the services, 1 Postgres, 1 Redis, 5 GB object storage, 100 GB egress, 100% average CPU load and 5 developers. EUR per month, excluding VAT, prices as of October 2026, USD converted at $1 = €0.89.

### Fly.io: €239.22/month

Fly.io performance machines in Amsterdam, running all month, one Managed Postgres Basic cluster per database and Upstash Fixed 250 MB per Redis.

| Line | Detail | EUR/month |
| --- | --- | --- |
| [Platform and seats](https://docs.fly.io/about/pricing) | No platform or seat fees | €0 |
| [Performance machines](https://docs.fly.io/about/pricing) | 2 dedicated vCPU + 4 GB in Amsterdam, all month | €60.97 |
| [Managed Postgres × 1](https://docs.fly.io/mpg/) | Basic at $38 plus storage | €34.07 |
| [Upstash Redis × 1](https://docs.fly.io/upstash/redis/) | Fixed 250 MB at $10, on the Fly invoice | €8.90 |
| [Tigris object storage](https://www.tigrisdata.com/pricing/) | 5 GB, first 5 GB free, then $0.02 | €0 |
| [Egress](https://docs.fly.io/about/pricing) | 100 GB at $0.02 per GB from Europe | €1.78 |
| [AI code review](https://www.coderabbit.ai/pricing) | CodeRabbit Essentials, 5 × $30 | €133.50 |
| **Total** |  | **€239.22** |

### Rock8Cloud Mercury: €28.70/month

| Line | Detail | EUR/month |
| --- | --- | --- |
| Mercury plan | 1 vCPU + 2 GiB pool, flat price | €20 |
| CPU add-ons | 3 × 0.25 vCPU at €2.10 | €6.30 |
| Memory add-ons | 4 × 256 MiB at €0.60 | €2.40 |
| Team seats | 5 developers, unlimited members | €0 |
| Postgres × 1 | 0.25 vCPU + 256 MiB each, from the pool | €0 |
| Redis × 1 | 0.25 vCPU + 256 MiB each, from the pool | €0 |
| Object storage | 5 GB of the 5 GB included | €0 |
| Egress | 100 GB, no per-GB fee | €0 |
| AI code review | Every pull request, from the €5 monthly AI budget | €0 |
| **Total** |  | **€28.70** |

| Rock8Cloud plan | Fits this stack | EUR/month |
| --- | --- | --- |
| Pluto | No, storage exceeds the quota | €26.75 |
| Mercury | Yes | €28.70 |
| Earth | Yes | €105 |

Difference: €210.52/month, €2,526.24/year.

### How to read this comparison

- Rock8Cloud reserves a CPU and memory pool for your services all month, so its bill is the same at 1% or 100% CPU load. Extra capacity is fixed-price add-on units, never metered usage.
- Usage-billed and serverless platforms bill what code uses, so an app that sits idle or scales to zero is cheap there. That is a real advantage for low-traffic, request-driven apps.
- In practice, servers run nonstop. Production APIs, background workers, queue consumers, schedulers and websocket servers stay up all month so they can answer at any moment, and they hold their memory the whole time. Workers and queue consumers also use CPU whenever they poll and process.
- cpuLoadPercent models the difference. 100 compares like-for-like with reserved capacity and fits always-on services under steady load. Lower it for request-driven apps that sit idle most of the day, where usage billing genuinely costs less.
- Postgres and Redis are priced always on at every vendor, because a production app, or a prototype someone is testing, has to answer whenever it is opened.
- Fly bills machines per second while they run. Performance machines are dedicated and start at 1 vCPU with 2 GB, so a small service on dedicated CPU still needs a whole machine. This estimate packs your total compute, so it understates Fly when you run many small services. ([source](https://docs.fly.io/about/pricing))
- Fly stops idle machines by default and starts them on the next request, and stopped machines pay no CPU or RAM. That saves real money for request-driven apps. Servers that run nonstop, like workers, queue consumers and websocket servers, never stop and pay all month. ([source](https://docs.fly.io/launch/autostop-autostart/))
- Fly shared-CPU machines are cheaper but get a 6.25% CPU quota once their burst balance runs out, which is not comparable to reserved capacity. ([source](https://docs.fly.io/machines/cpu-performance/))

Price your own stack against Fly.io: https://rock8.cloud/vs/fly#calculator

## A shared slice or a reserved core.

Fly documents exactly what a shared vCPU gets. Rock8Cloud reserves the capacity your plan names, so you compare prices for performance you keep.

|  | Fly.io | Rock8Cloud |
| --- | --- | --- |
| CPU you actually get | A shared vCPU is a 6.25% slice - 5 ms per 80 ms period, throttled when the burst balance is spent ([source](https://docs.fly.io/machines/cpu-performance/)) | Your plan's vCPUs are reserved for you. Full performance, no quota to manage |
| Comparable machine | performance-1x with 2 GB is $34.25 a month in Amsterdam ([source](https://docs.fly.io/about/pricing)) | Mercury is €20 a month - a 1 vCPU + 2 GiB pool with build minutes and a €5 AI allowance inside |
| Pricing model | Per machine, per region, per volume, summed on the invoice | One plan price for a pool your services share |
| Deploy model | Machines and a config file, powerful once you learn it | Push the repo, get a live URL. No config to learn |
| AI code review | Not part of the platform | Included on every pull request |
| Coding agents | Not part of the platform | Sandbox agents build tasks and open pull requests, AI allowance included |
| Agent context | An agent can drive the hosting. Reviews and tasks live elsewhere | One platform over MCP - code, reviews, deploys and runtime in one context |
| Global placement | Runs your app close to users in dozens of regions - real edge strength | We run EU data centres and put the money into your reserved pool instead |

Fly.io figures as of October 2026, Amsterdam region: shared-cpu-1x from $2.27 a month with 256 MB, performance-1x with 2 GB at $34.25 a month after the October 1 memory price rise to $6 per GB. The shared CPU quota is 5 ms per 80 ms period.

Sources:

- [Fly.io pricing](https://docs.fly.io/about/pricing)
- [CPU performance docs](https://docs.fly.io/machines/cpu-performance/)

## Rock8Cloud pricing

### Plans

| Plan | Monthly billing | Annual billing | CPU + memory pool | Add-on 0.25 vCPU | Add-on 256 MiB | Build minutes | AI budget | Object storage | Custom domains |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Pluto | €5/month | €4.50/month (€54 a year) | 0.25 vCPU + 256 MiB | €2.25/month | €0.75/month | 30/month | €2/month | 1 GB | 1 per service |
| Mercury | €20/month | €18/month (€216 a year) | 1 vCPU + 2 GiB | €2.10/month | €0.60/month | 100/month | €5/month | 5 GB | 1 per service |
| Earth | €105/month | €94.50/month (€1,134 a year) | 5 vCPU + 12 GiB | €2/month | €0.50/month | 1,000/month | €20/month | 25 GB | 2 per service |

- All prices in EUR, excluding VAT. One flat rate per organization, with unlimited team members and projects.
- Annual billing takes 10% off the plan price. Add-ons carry no annual discount.
- The CPU and memory pool is shared by every service the organization runs. Each service takes a slice from 0.25 vCPU and 256 MiB up, resizable anytime. Sleeping services use none.
- Grow the pool with add-on units of 0.25 vCPU or 256 MiB, in any quantity, on every plan. The price is the quantity you pick, never metered.
- Each managed PostgreSQL or Dragonfly (Redis) starts at 0.25 vCPU + 256 MiB from the pool. Object storage (S3) does not draw from the pool.
- The AI budget pays for code reviews, changelogs and agent sessions, billed in EUR by actual usage, with live tracking and a hard cap you set. Top-ups never expire.
- Mercury is free for 30 days, no credit card required.
- Enterprise: the whole platform on your own hardware or private cloud, operated by us or by your team, with your own AI models and keys, custom blueprints that start every new app on your code standards, SSO, custom limits and a contractual SLA. Details: https://rock8.cloud/enterprise. Contact support@rock8.cloud.

### Estimate a workload

Monthly price = plan price + CPU add-on price × ceil((vCPU needed - pool vCPU) / 0.25) + memory add-on price × ceil((MiB needed - pool MiB) / 256). On annual billing, use the annual plan price, add-ons stay the same. Count each database in the CPU and memory needed. Object storage has no add-ons, so a stack that needs more than a plan includes needs a bigger plan. Egress has no per-GB fee.

Example, 4 vCPU + 8 GiB with no databases:

| Plan | Monthly billing | Annual billing |
| --- | --- | --- |
| Pluto | €62/month | €61.50/month |
| Mercury | €59.60/month | €57.60/month |
| Earth | €105/month | €94.50/month |

Cheapest plan for this workload: Mercury. Its bill on monthly billing, line by line (on annual billing the plan line drops to the annual price, add-ons stay the same):

| Line | Detail | EUR/month |
| --- | --- | --- |
| Mercury plan | 1 vCPU + 2 GiB pool, flat price | €20 |
| CPU add-ons | 12 × 0.25 vCPU at €2.10 | €25.20 |
| Memory add-ons | 24 × 256 MiB at €0.60 | €14.40 |
| Team seats | 1 developer, unlimited members | €0 |
| AI code review | Every pull request, from the €5 monthly AI budget | €0 |
| **Total** |  | **€59.60** |

Price your own stack, with databases, egress and a comparison against Vercel, Railway, Render and Fly.io: https://rock8.cloud/pricing#calculator

Full feature table: [https://rock8.cloud/pricing](https://rock8.cloud/pricing).

## Get started

- [Start 30 days free](https://app.rock8.cloud): no credit card required.
- Free migration from Fly.io: our engineers move your apps, databases, environment variables and domains with you, no commitment. Start on [Discord](https://discord.gg/Y8eS72nBbn) or email support@rock8.cloud.
- Or connect your agent to the MCP server at https://app.rock8.cloud/mcp and it does the move: provisions Postgres and Redis, sets your config and ships your app.