Choose Moltern when
You want apps, databases, catalog software and private coding agents in one workspace, with scoped access and organization governance.
Discuss your stack ↗MolternMoltern vs Fly.io
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Moltern vs Fly.io
Fly.io gives developers regional Machines, volumes, private networking and a CLI-oriented operating model.
Flight paths artwork / 31
A working app rarely runs alone. It has data, background work, secrets and people who need access. Fly.io gives developers regional Machines, volumes, private networking and a CLI-oriented operating model. Compare that starting point with Moltern’s shared workspace before deciding what your team should operate.
Start with the right job.
What Fly.io is built around
Fly.io gives developers regional Machines, volumes, private networking and a CLI-oriented operating model.
Review notes & documentation ↓42 · feature dimensions
Look beyond the first deployment.
What is included, what depends on a plan, and what your team must assemble or operate.
42 / 42 · rows shown
| Capability | Moltern | Fly.io |
|---|---|---|
| Build & deploy | ||
| Git deployments | MolternDocumented Repository, branch and build settings | Fly.ioYour team operates it |
| Static sites | MolternDocumented Static and server applications | Fly.ioYour team operates it |
| Container workloads | MolternDocumented Application builds and packaged services | Fly.ioDocumented Docker / OCI workload support Fly Machines |
| Background workloads | MolternDocumented Run supported app and service processes | Fly.ioDocumented |
| Environment separation | MolternDocumented Production, staging, development and preview environments | Fly.ioPlan / configuration |
| Deployment history & rollback | MolternDocumented Release history and application rollbacks | Fly.ioDocumented |
| Services & data | ||
| Packaged service catalog | MolternDocumented Databases, CMS, analytics, automation and more | Fly.ioSeparate service / integration |
| SQL databases | MolternDocumented Database services with service-specific setup | Fly.ioPlan / configuration Provision a dedicated database service Managed Postgres |
| Caches & queues | MolternDocumented Deploy supported catalog services | Fly.ioYour team operates it Install, patch and back up the database yourself |
| Persistent storage | MolternDocumented Workload storage with workspace allowances | Fly.ioPlan / configuration Attach durable storage with its own lifecycle Fly Volumes |
| Private service connections | MolternDocumented Select targets and runtime connection variables | Fly.ioPlan / configuration Private connectivity requires workload configuration 6PN |
| AI service stacks | MolternDocumented Catalog AI services, with workload-specific resources | Fly.ioSeparate service / integration |
| Agent workspaces | ||
| Coding-agent workspace | MolternDocumented Private Codex, Claude Code, Gemini CLI and OpenCode workspaces | Fly.ioSeparate service / integration |
| Agent provider sign-in | MolternDocumented Save supported provider sessions or API keys | Fly.ioSeparate service / integration |
| Per-target agent permissions | MolternDocumented Read context or connect to explicitly selected workloads | Fly.ioYour team operates it |
| Browser terminal | MolternDocumented Multiple terminal tabs in private workspaces | Fly.ioDocumented Shell or process execution in the runtime |
| Persistent agent files | MolternDocumented Optional persistent workspace, within storage quota | Fly.ioSeparate service / integration |
| Remote desktop | MolternPlan / configuration Omarchy desktop profile; availability and host capacity apply | Fly.ioSeparate service / integration |
| Run & observe | ||
| Application & service logs | MolternDocumented Deployment and runtime visibility | Fly.ioDocumented |
| Resource monitoring | MolternDocumented Workload CPU, memory and status views | Fly.ioDocumented |
| Automatic instance scaling | MolternPlan / configuration Eligible workloads; min/max instances and CPU target | Fly.ioPlan / configuration |
| Domains & TLS routes | MolternDocumented Application domains and route configuration | Fly.ioDocumented |
| Secret handling | MolternDocumented Build/runtime variables; separate use and reveal permissions | Fly.ioDocumented |
| Event webhooks | MolternDocumented Workspace event delivery and webhook management | Fly.ioDocumented |
| Identity & governance | ||
| Organizations & workspaces | MolternDocumented Shared organization with distinct workspace ownership | Fly.ioDocumented |
| Scoped roles & groups | MolternDocumented Environment and resource scopes, groups and expiry | Fly.ioPlan / configuration Project or team-level roles; inspect resource scope |
| SAML / OIDC SSO | MolternDocumented Verified domains, provider checks and SSO enforcement | Fly.ioConfirm requirements |
| SCIM provisioning | MolternDocumented Synchronize users and groups; grant workload access separately | Fly.ioConfirm requirements |
| Audit history | MolternDocumented Organization security history and audit exports | Fly.ioConfirm requirements |
| Access reviews & approvals | MolternDocumented Review access and protected-action requests | Fly.ioConfirm requirements |
| Runtime primitives | ||
| Public sandbox execution SDK | MolternDifferent product scope Public discovery endpoints; no supported sandbox execution SDK | Fly.ioSeparate service / integration Platform management API differs from a sandbox execution SDK Sprites |
| Platform CLI | MolternDifferent product scope Provider CLIs in agents; standalone Moltern CLI coming later | Fly.ioDocumentedflyctl |
| Unrestricted root VM access | MolternDifferent product scope Workload terminals; unrestricted root VMs are not promised | Fly.ioDifferent product scope |
| Environment snapshots & restore | MolternConfirm requirements Persistent files; VM memory snapshots are not documented | Fly.ioPlan / configuration Verify disk, memory and resume coverage separately |
| GPU compute | MolternConfirm requirements AI catalog services; confirm GPU capacity for your deployment | Fly.ioConfirm requirements |
| Hostile-code isolation | MolternConfirm requirements Private workloads; review hostile-code isolation requirements | Fly.ioConfirm requirements |
| Costs & limits | ||
| Budgets & spend guardrails | MolternPlan / configuration Cost centers, budgets and eligible capped PAYG overages | Fly.ioPlan / configuration |
| Capacity admission & quotas | MolternDocumented Workload slots, CPU/RAM and storage allowances | Fly.ioDocumented Configure resource size, quota and lifecycle rules |
| Idle lifecycle | MolternPlan / configuration Hobby may sleep; Pro production has no Hobby sleep behavior | Fly.ioPlan / configuration |
| On-premises deployment | MolternPlan / configuration Available by arrangement for larger organizations | Fly.ioDifferent product scope |
| Billing granularity | MolternDocumented Plan allowances, measured usage and storage views | Fly.ioDocumented |
| Backup & recovery responsibility | MolternYour team operates it Service-specific; assign owners and test restoration | Fly.ioPlan / configuration |
How to read this table
“Confirm requirements” means the reviewed documentation does not establish an equivalent workflow. It does not mean the feature is impossible. Plan and configuration requirements still apply to documented features.
Documented Plan / configuration Your team operates it Separate service / integration Confirm requirements Different product scope
The limits that change the decision.
Check the exact plan and region before committing. Resource limits, lifecycle rules and billing units are different questions.
Capacity & concurrency
Moltern
Apps, top-level services and coding agents count toward workload quota. Agent CPU and RAM are reserved while running; persistent storage uses the workspace pool. Maximum autoscaling capacity must fit available quota.
Fly.io
Check per-service CPU/RAM, replica counts, build concurrency and account quotas. Private networking and autoscaling may depend on the service type or plan.
Runtime & persistence
Moltern
Hobby services may sleep after inactivity. Pro is intended for production without that sleeping behavior. Persistent agent files survive restarts; running processes and in-memory state are not automatically resumed.
Fly.io
Distinguish continuously running services from jobs and functions. A persistent disk can change scaling, replica and recovery options; verify the exact workload configuration.
What goes on the bill
Moltern
Check current in-product plan allowances, measured usage, storage and eligible overages. PAYG has an explicit monthly cap; a budget alert and a hard spending guardrail are different controls.
Fly.io
Include service runtime, databases, build usage, persistent storage and outbound traffic. Team features and private deployment options can have separate plan requirements.
- 01
Map the app and its dependencies.
List repositories, workers, data stores, secrets, domains and who owns each one. Keep an export and a rollback route before moving data.
- 02
Build a staging environment.
Deploy the app, attach only the services it needs, and test routes, persistence, logs and access rules with representative traffic.
- 03
Compare the whole operating cost.
Include build time, runtime, storage, network traffic, AI-provider charges and your team’s operating time. Move production only after recovery and ownership are clear.
Review notes & documentation
Reviewed 26 October 2026 against public product documentation. This is a workflow comparison, not a benchmark, certification assessment or guarantee of feature parity. Linked products, enterprise agreements and self-managed installations have their own terms.
Put it into practice
Deploy the code you own
Connect a repository and branch, review the build and start commands, then set the runtime port and health check. Static sites and web services have different operating needs.
Connect data privately
Put the service in the appropriate environment and use explicit private connections where supported. Keep server credentials out of browser code and source control.
Check the release people will use
Inspect deployment status and logs, verify the URL and test the application’s main workflow. Record who owns configuration changes, service upgrades and recovery.
Detailed instructions are maintained in the product documentation.
Questions before you start
Can I keep my existing framework?
Use a supported runtime or a Dockerfile. Review the application guide for your build output and server requirements.
Who owns backups and recovery?
Name an owner and review the service-specific persistence and recovery instructions before relying on its data.
What should I check when a deployment fails?
Start with deployment logs, build commands, runtime port, health checks and required variables, then follow the troubleshooting guide.
Keep exploring
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