Fly Machines vs Spider
Comparing architecture, runtime limits, open-source licenses, and monthly costs for autonomous agent pipelines.
Detailed Specifications & Compatibility Matrix
Extracted directly from GitHub REST API & official developer documentation
| Technical Feature / Metric | Fly Machines | Spider |
|---|---|---|
| Developer / Organization | Fly.io Inc. (Kurt Mackey & Team) | Spider Rust Org (Jeff Mendez) |
| Open-Source Engine | ✓ Open Source (Apache-2.0) | ✓ Open Source (MIT) |
| GitHub Stars (Repo/SDK) | ★ 1,719 GitHub Stars | ★ 2,795 GitHub Stars |
| Core Repository Language | Go | Rust |
| Supported SDK Clients | ||
| Self-Hosted Deployment | Hosted Only | ✓ Supported |
| Docker / Container Ready | ✓ Official Image | ✓ Official Image |
| Model Context Protocol (MCP) | Standard REST/gRPC | ✓ Native MCP |
| Billing Architecture | usage based | free |
| Developer Free Tier | ✓ Yes 3 shared-cpu-1x microVMs allowance | ✓ Yes 1,000 free credits on sign-up |
| Entry Paid Tier (Monthly) | $1.94 USD / mo | $15 USD / mo |
| Pricing & Cost Architecture | Pay-as-you-go billed per second: shared CPU microVMs start at ~$0.0000022/second (~$1.94/month if running 24/7). Stopped machines pay only for attached NVMe disk storage ($0.15/GB/mo). | Core Rust crawler is 100% free and open-source under MPL-2.0. Managed Spider Cloud API offers a free tier of 1,000 credits, with paid plans beginning at $15/mo. |
| Key Engineering Insight | Operates custom bare-metal servers across 35+ global edge datacenters, booting Linux kernels directly on KVM without container orchestration overhead. | Independent benchmarks demonstrate Spider crawling large e-commerce catalogs at over 100,000 pages per minute while maintaining RAM consumption under 150MB. |
Strengths & Trade-Offs
Objective engineering evaluation of both platforms
Fly Machines Evaluation
Key Advantages
- ✓ Sub-300ms boot times for custom Docker images running in 35+ global edge data centers close to end users
- ✓ Full persistent NVMe volume support with customizable memory/vCPU ratios per individual machine instance
- ✓ Fast REST API allowing agents to dynamically spawn, pause, snapshot, and destroy microVMs programmatically
Limitations & Trade-Offs
- ✕ Requires managing base Linux Docker images, security firewall configurations, and internal WireGuard routing
- ✕ Lacks a specialized high-level code execution SDK out of the box (requires building custom API wrappers)
Spider Evaluation
Key Advantages
- ✓ High-performance Rust architecture delivering benchmark speeds up to 10x faster than Python Scrapy
- ✓ Minimal CPU and RAM footprint allowing dense deployment on lightweight VPS instances or containers
- ✓ Permissive Mozilla Public License 2.0 open-source engine with built-in headless browser and HTTP modes
Limitations & Trade-Offs
- ✕ Smaller developer community and fewer pre-built third-party plugins compared to Playwright or Puppeteer
- ✕ Extending low-level network and HTML parsing logic requires proficiency with the Rust toolchain
Source Quotes
Direct excerpts from official documentation backing our extracted specifications
Fly Machines Documentation Proof
"Shared CPU instances start at $0.0000022/second (~$1.94/mo)."
"Free resource allowances include up to 3 shared-cpu-1x microVMs."
"Global microVM platform running on Fly.io bare metal hardware."
Spider Documentation Proof
"Spider Cloud paid subscriptions start at $15/month for 100,000 pages."
"Free tier provides 1,000 credits to test API endpoints."
"Open source engine available under MPL-2.0 for self-hosted instances."
Frequently Asked Questions: Fly Machines vs Spider
Architectural trade-offs and decision criteria
Is Fly Machines or Spider cheaper for developers?
Fly Machines has a starting price of $1.94/mo (usage based), while Spider starts at $15/mo (free). Fly Machines includes a free tier (3 shared-cpu-1x microVMs allowance). Spider offers a free tier (1,000 free credits on sign-up).
Can I self-host Fly Machines and Spider in my own infrastructure?
Fly Machines is a cloud-managed service only. In comparison, Spider is available for self-hosting with MIT licensing.
Do Fly Machines and Spider support the Model Context Protocol (MCP)?
Fly Machines does not currently list native MCP server compatibility. Spider fully supports Model Context Protocol integrations.
Which programming languages have official SDKs for Fly Machines vs Spider?
Fly Machines provides official SDKs in: go, curl, python. Meanwhile, Spider supports: rust, python, typescript.