Heroku vs Fly.io(2026)
Heroku is better for teams that need large add-ons ecosystem. Fly.io is the stronger choice if true global deployment. Heroku is paid (from $5/month) and Fly.io is freemium (from $1.94/month).
Full feature breakdown, pricing details, and pros & cons below.
By Bikram NathLast updated
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Heroku
Heroku is a platform as a service (PaaS) that enables developers to build, run, and operate applications entirely in the cloud.
Starting at $5/month
Visit HerokuFly.io
Fly.io transforms containers into micro-VMs that run on hardware in 35+ cities around the world, close to your users.
Starting at $1.94/month
Visit Fly.ioHow Do Heroku and Fly.io Compare on Features?
| Feature | Heroku | Fly.io |
|---|---|---|
| Pricing model | paid | freemium |
| Starting price | $5/month | $1.94/month |
| Git push deploy | ✓ | — |
| Add-ons marketplace | ✓ | — |
| Managed PostgreSQL | ✓ | — |
| Review apps | ✓ | — |
| CI/CD pipeline | ✓ | — |
| Global edge deployment | — | ✓ |
| Docker-based | — | ✓ |
| 35+ regions | — | ✓ |
| Persistent volumes | — | ✓ |
| Private networking | — | ✓ |
Heroku Pros and Cons vs Fly.io
Heroku
Fly.io
Deep dive: Heroku
When to choose Heroku
Heroku is defensible only when you already own it or are locked into the Salesforce ecosystem and can't migrate. The economics are poor: starting at $5/month (hobby tier) quickly becomes $25+ per dyno + database costs, making total projects $50-150+/month for basic setups. Choose Heroku if: you're inheriting a legacy codebase already on Heroku (migration cost exceeds staying), you have enterprise support contracts and can't renegotiate, or your team has zero infrastructure knowledge and must avoid DevOps entirely. The ecosystem of add-ons (SendGrid, Papertrail, Redis Cloud, etc.) is genuinely useful if you're not price-sensitive. Heroku becomes catastrophically wrong when: you care about unit economics (competitors offer 3-5x better pricing), you're building new projects (choose literally anything else), you need modern DX (deploy times are slow, UI is dated), or you value community momentum (Heroku's is stalled). The 2022 removal of the free tier killed Heroku's last compelling angle. New projects on Heroku are a strategic error.
Real-world use case
An agency managing 8 legacy client Rails apps stayed on Heroku because migrating each would cost $20k and risk downtime. Their monthly bill: $380 (2 dynos × $25, Standard-1X tier; 1 PostgreSQL Standard Database at $50; SendGrid at $20; Papertrail logs at $10; New Relic APM at $50). This would cost $60/month on Fly or Render for identical workloads. The single advantage: zero DevOps. When a database failed, Heroku's one-click failover saved 2 hours vs AWS manual recovery. Their developer onboarding took 15 minutes—'just push to main'—versus Fly's 2-day Docker learning curve. The tradeoff was clear: they paid $3,600/year for convenience and safety, consciously accepting that identical scale on Fly would cost $720/year. For legacy codebases with zero infrastructure talent and annual revenue >$50k, this math works. For new projects, it's inexcusable.
Hidden gotchas
The build pack system is a black box—dependencies sometimes mysteriously fail to install because Heroku's Ruby/Node version detection guessed wrong. Error messages are cryptic: 'H12 Request timeout' gives no indication whether it's your code, the buildpack, or Heroku's infra. Sleeping dynos are a vestigial 'feature'—free tier apps still sleep after 30 minutes, and this setting is buried in dashboard settings that new developers never find. Ephemeral filesystems mean any writes outside /tmp vanish on dyno restart; Heroku's docs mention this casually, but many developers learn it in production. Database backups are included but restores require manual intervention via Heroku CLI—no self-service restoration. Add-on pricing is predatory: SendGrid's 'free' tier on Heroku is limited to 400 emails/month, while standalone SendGrid is 1,000/month—you're paying a Heroku tax. Scaling dynos vertically (larger dyno size) is expensive and often less effective than horizontal scaling, but the UI nudges you toward vertical. Postgres replica standby pricing (read replicas) is 50% of the primary—on Heroku, not all providers. Finally, Salesforce's ownership creates a perception of instability; annual price increases and deprecations (like free tier removal) suggest Heroku is a cash-flow product, not a core business focus.
Pricing breakdown
Heroku's Eco plan starts at $5/mo for 1,000 dyno hours (shared across all Eco dynos). Basic plan is $7/mo per dyno with no sleep. Standard-1X is $25/mo (512 MB, no sleep, horizontal scaling). The Postgres add-on starts free (10K rows, 1 GB), Mini at $5/mo (10M rows), and Basic at $9/mo. The real cost escalation: once you need worker dynos, scheduler, and a production database, a modest app quickly hits $50-100/mo. Heroku's pricing is predictable but premium — equivalent compute on Render or Railway costs 30-50% less.
Deep dive: Fly.io
When to choose Fly.io
Fly.io is the choice for teams prioritizing global latency and willing to embrace Docker-native deployments. Pick Fly if you're running containerized apps needing presence in 35+ regions, want sub-100ms latency for users worldwide, or need competitive per-minute pricing without AWS's complexity tax. It's ideal for: real-time apps (gaming, live collaboration), geographically distributed teams, teams already proficient with Docker/containers, and developers who value control. Fly becomes the wrong choice when: your team is Docker-unfamiliar and learning curve is a blocker, you need managed PostgreSQL as your primary feature (it exists but is clunky), you want one-click deployments without CLI involvement, or your app is static/JAMstack (overkill and expensive). The steep learning curve isn't marketing hype—it's real. Developers report spending 2-3 days getting first deployments stable. Cost-wise, Fly stays cheap only if you optimize aggressively; inefficient container configs create billing surprises.
Real-world use case
A European SaaS company building a real-time collaborative editor chose Fly.io to compete with giants by offering true sub-50ms latency in 12 regions. They deployed a Node.js app in Docker containers. Month 1 cost: $15 (minimal traffic). By month 6 with 5,000 active users, costs stabilized at $120/month—$80 for compute, $40 for managed PostgreSQL and volumes. Their latency metrics: US-East 45ms, EU-Central 12ms, APAC 98ms. The tradeoff: a single engineer spent 1 week debugging volume persistence (Fly volumes don't replicate automatically), discovering users' data disappeared on container restarts. They learned to use PostgreSQL instead of local volumes. Deployment to production took 2 minutes from git push via Fly CLI. The hidden win: Fly's pricing remained predictable; no surprise jumps like Heroku or Render. When they hit 10k users, scaling from 2 to 4 container instances cost just $30 more.
Hidden gotchas
Volumes (local storage) don't auto-replicate—data loss is a trap for developers assuming distributed storage works like managed services. PostgreSQL on Fly.io has a config gotcha: SSL must be explicitly enabled in connection strings, otherwise production deployments succeed but apps mysteriously fail at runtime. Memory limits are enforced harshly—a Node.js app with a memory leak will be OOMKilled without warning; logs show only 'received signal SIGKILL.' The CLI requires constant authentication; tokens expire silently, causing cryptic 'unauthorized' errors mid-deploy. Billing is per-minute and can spike if apps crash in loops—a buggy deploy restarting every 10 seconds costs 3x as much as expected. Fly's Postgres requires manual read-replica setup (unlike Render's one-click managed database), adding complexity. Building Docker images locally and pushing to Fly's registry has undocumented size limits (image layers over 5GB fail silently). IPv6-only deployments are the default; legacy clients expecting IPv4 see 'connection refused' errors. Cold starts exist on free tier despite marketing claims of 'no cold starts'—they happen after 30 days of inactivity.
Pricing breakdown
Fly.io offers a free allowance of 3 shared-CPU VMs (256 MB each), 3 GB persistent storage, and 160 GB outbound transfer per month. Beyond that, shared-CPU VMs start at $1.94/mo (1 shared CPU, 256 MB). Dedicated-CPU VMs start at $31/mo (1 CPU, 2 GB RAM). Egress is $0.02/GB after the free tier. The pricing model is usage-based — you pay for uptime, not requests. For a globally distributed app with 3 regions, expect $15-50/mo for a lightweight service. The gotcha: persistent volumes are region-locked and cost $0.15/GB/mo, and multi-region Postgres requires a volume per region.
Should You Use Heroku or Fly.io?
For most teams, Heroku is the better default: it offers large add-ons ecosystem and is paid (from $5/month). Choose Fly.io instead if true global deployment matters more than removed free tier in 2022. There is no universal winner — the right pick depends on your budget, team size, and whether you value large add-ons ecosystem or true global deployment more.
Choose Heroku if…
- •Large add-ons ecosystem
- •Mature platform
- •Good documentation
Choose Fly.io if…
- •True global deployment
- •Docker-native
- •Low latency globally