How a call runs
An application calls the API over HTTPS. The API is the control plane. It places the runtime on a compute host over gRPC.cellfabric is the compute controller on that host, the compute brain. It manages the host’s compute. It starts the sandbox or the agent and restores a template or a snapshot onto local NVMe. cellcore is the daemon inside the sandbox or agent. cellfabric uses it to run code, run a command, read and write files, use git, and open a terminal. The host reaches that daemon over ttrpc on vsock. The same calls are available over gRPC.
A sandbox is ready in ~25 ms.
When you attach an Identity provider, its secrets are injected for that run.
cellproxy is the service edge for the region. A browser, a published port, or the web terminal arrives there. It checks the credential and forwards to cellrouter on the host that holds the runtime. cellrouter opens the port the process is listening on. The public name is {port}-{runtime_id}.service.gravixlayer.ai. The credential stays at the edge.
The SSH gateway is the shell door in the region. A client connects with a public key, and the gateway opens the session on that sandbox.
The MCP gateway is the tool door on that host. A tool call brings the credential for that use. The credential is not stored on the host, and it does not enter the sandbox.
What each part keeps
The API keeps the account: runtimes, templates, snapshots, keys, providers, and billing. Identity and access hold the keys and the providers. The API decides, and the host enforces that decision. Observability keeps the record of the run: traces, events, and logs. A template is the image a new sandbox or agent boots from. Gravix Layer ships base templates, and you can build your own. A snapshot is a named image of one you already ran. Both live in the region. A fork starts independent runtimes from a live sandbox or from a snapshot. The root disk is local NVMe on the compute host. It is private to that sandbox or agent, and it is removed when you kill the runtime. Block storage is a persistent volume in the region. The sandbox attaches it as a block device, and the volume remains after the sandbox is gone. Egress is deny-by-default. eBPF in the Linux kernel on the host allows only the destinations named in the attached network policy.Use it
Quickstart
Create a runtime and run code.
Python and TypeScript
The SDK calls.
CLI
The same calls from the shell.
Web services
A public URL for a port inside the runtime.