Pick Fly.io if you want apps running close to users on Firecracker microVMs across its global Anycast network (18 regions worldwide as of 2026), with per-second usage billing and low-level VM control. Pick RailPush if you want a fixed-price, EU-hosted PaaS that an AI agent can fully operate: a hosted remote MCP endpoint with 286 tools, a no-auth agent-signup API, git/Docker/one-click/agent deploy surfaces, and a real free tier with no credit card. Both build from Dockerfiles and auto-detect frameworks; they differ most on pricing predictability and AI-native operation.
| Feature | Fly.io | RailPush |
|---|---|---|
| Primary deploy model | flyctl CLI (fly launch / fly deploy), Dockerfile builds, config via fly.toml | git push, Docker image, one-click button, or AI agent via MCP |
| Framework auto-detection | Yes (generates Dockerfile/config on fly launch) | Yes (20+ frameworks) |
| AI-agent deploy API (no-auth signup) | No — flyctl auth required | Yes — agent-signup API needs no auth to start |
| Hosted remote MCP for AI agents | Experimental local stdio MCP that wraps flyctl (runs on 127.0.0.1, needs flyctl installed + authed); flyctl can also deploy your own remote MCP servers | Hosted remote MCP at mcp.railpush.com (Streamable HTTP + SSE), 286 tools |
| Free tier | No permanent free tier; limited free trial (≈2 VM-hours / 7 days), card required to continue | Yes — $0 plan, 1 service + 1 Postgres + 1 Redis, no credit card |
| Pricing model | Usage-based, per-second compute metering | Fixed monthly per resource (no per-minute/second metering) |
| Managed PostgreSQL | Managed Postgres (Percona-backed, PG 16, HA + backups + PgBouncer pooling) | Managed PostgreSQL with PITR + daily backups |
| Other managed databases | Redis via Upstash integration; object storage via Tigris (S3-compatible) | MySQL 8.0, MongoDB 7.0, Redis, Meilisearch, S3-compatible storage (MinIO), RabbitMQ |
| Deploy strategies | Rolling, canary, blue-green, immediate; rollback via redeploy of a prior release | Rolling, blue-green, canary; instant rollbacks; full deploy history; preview environments |
| Scaling | Autostop/autostart (scale to zero); metrics-based autoscaler | Horizontal autoscaling up to 50 instances; free-tier scale-to-zero (~60s wake) |
| Global regions / edge | 18 regions worldwide on a global Anycast network (after 2025 region consolidation) | EU region |
| GPU support | GPU Machines being deprecated — unavailable after July 31, 2026; new orgs need billing approval | Yes — NVIDIA RTX 4000 Ada, 20GB VRAM |
| Infrastructure as Code | fly.toml app config | Blueprints (railpush.yaml) |
| Security & governance | Firecracker VM isolation, private networking (WireGuard), org/token access | WAF rules, network policies, gVisor sandboxing, audit logs, deploy approvals, scoped API keys |
Pick Fly.io: Choose Fly.io when you need apps running close to users across multiple global regions with per-second billing and low-level Firecracker/Machines control.
Pick RailPush: Choose RailPush when you want AI agents to deploy and operate your infra via a hosted MCP, with predictable fixed pricing and a real free tier.
Migrating from Fly.io to RailPush is mostly a re-platforming exercise: both build from Dockerfiles, so your container setup carries over, and you translate fly.toml settings into a railpush.yaml Blueprint (or use git/Docker/one-click deploy). Re-create managed dependencies as RailPush services — Postgres, Redis, MySQL/MongoDB, object storage, queues — and import data via standard dumps/restores. Note the regional trade-off: RailPush is EU-hosted, so it's a strong fit for EU/GDPR-centric apps but not a drop-in replacement for Fly.io's multi-region global edge.
Yes, but it's a different shape. Fly.io ships an experimental 'fly mcp server' that runs locally on your machine and wraps the flyctl CLI — it requires flyctl installed and authenticated and binds to 127.0.0.1 (flyctl can also help you deploy your own remote MCP servers as Fly apps). RailPush runs a hosted, remote MCP at mcp.railpush.com (Streamable HTTP + SSE) exposing 286 tools, plus a no-auth agent-signup API, so an AI agent can sign up and deploy without any local CLI.
No. Fly.io retired its permanent free allowances and now offers a limited free trial (roughly 2 VM-hours or 7 days, whichever comes first); after that you must add a payment method. RailPush offers a $0 plan (1 service + 1 PostgreSQL + 1 Redis) with no credit card required.
Fly.io is usage-based and meters compute per second, so you pay for exactly what runs — flexible, but harder to predict. RailPush uses fixed monthly per-resource pricing (separate plan tiers per service size) with no per-minute or per-second metering, which makes monthly cost predictable.
Partly. RailPush covers the core PaaS workflow well and adds AI-native operation, but it's EU-hosted (single region). Fly.io's strength is running across 18 regions on a global Anycast network. If multi-region edge latency is essential, Fly.io is stronger; if you're EU/GDPR-focused and want AI-agent operability and predictable pricing, RailPush fits better.
Fly.io offers Managed Postgres (Percona-backed PG 16 with HA, backups, and PgBouncer pooling), Redis via an Upstash integration, and S3-compatible object storage via Tigris. RailPush provides first-party managed PostgreSQL (with PITR + daily backups), MySQL 8.0, MongoDB 7.0, Redis, Meilisearch, MinIO object storage, and RabbitMQ.
This is changing. Fly.io is deprecating its GPU Machines — they become unavailable after July 31, 2026, and new organizations need billing approval to access them in the meantime. RailPush offers a first-party GPU plan (NVIDIA RTX 4000 Ada, 20GB VRAM), so if you need ongoing GPU compute, check current availability on each platform before committing.
Both can be driven by AI agents, but the integration differs. With Fly.io you run the local flyctl MCP server (authenticated) and point your editor at it. With RailPush, agents connect to the hosted remote MCP at mcp.railpush.com and can even start via the no-auth signup API, making fully agent-operated deploys more turnkey.
Fly.io is the stronger choice for globally distributed, latency-sensitive apps that benefit from Firecracker microVMs, a multi-region Anycast network (18 regions in 2026), and per-second billing. RailPush wins for teams that want AI agents to deploy and operate infra through a hosted MCP, with predictable fixed pricing and a genuine free tier — best for EU-focused, agent-driven workflows.
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