Every AI coding tool generates code. None of them solve what happens next.
Cursor writes your Python. Claude Code refactors your script. Windsurf
ships your feature. But running that code safely, in isolation, with
audit trails, without exposing your secrets, is still an unsolved problem.
That's what Jhansi.io is built for.
The mistake we made in v0.1
Our first execution model was simple. Send code as a string, run it in
an isolated container, return the output.
POST /v1/sandboxes/{id}/exec
body: { "code": "print('hello world')" }
It worked. But it had three fundamental problems.
| Problem | Why it breaks |
|---|---|
| Single file only | No multi-file projects, no shared modules, no dependencies. Not how production code works. |
| Full payload on every run | Even if nothing changed, you resent everything. Wasted bandwidth, added latency. |
| No foundation for delta sync | If you're sending everything every time, there's nothing to diff against. |
The insight
A sandbox should be a workspace, not a disposable container.
Give every sandbox a dedicated folder on disk. Files live there between
runs. Execution just says "run this file" — no payload, no resend, no waste.
This is the architecture shift in Jhansi.io v0.2.
What changed
Workspace per sandbox. Every sandbox gets a dedicated folder on disk
at creation time. Zero config locally, overridable in production via
PETRI_WORKSPACE_ROOT.
File upload API. Upload once. Upload only when something changes.
POST /v1/sandboxes/{id}/files
Files land in the sandbox workspace and persist between runs.
Exec by filename. No code in the request body. Just a filename.
POST /v1/sandboxes/{id}/exec
body: { "filename": "main.py" }
Jhansi.io mounts the workspace into a fresh isolated container and runs
the named file. The container dies. The workspace survives.
The flow
# Create once
curl -X POST /v1/sandboxes -d '{"language": "python"}'
# Upload when files change
curl -X POST /v1/sandboxes/{id}/files -F "[email protected]"
# Exec as many times as you need
curl -X POST /v1/sandboxes/{id}/exec -d '{"filename": "main.py"}'
What this unlocks
The persistent workspace is the foundation for everything coming next:
Delta sync — detect file changes, upload only diffs
Auto dependency detection — parse imports, install packages invisibly
Multi-file projects — real codebases, not toy scripts
If you're building AI agents that generate and run code, we want you in
our design partner program. Early access at jhansiio.featurebase.app
Jhansi.io — Build it. Run it. Ship it.
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