renest

Renest saves a ComfyUI or fine-tuning setup that already worked on a rented GPU — the model files, custom nodes, exact package versions and workflow — and brings it back on another Linux GPU machine, every file checked against its SHA-256. It promises that the files and dependencies come back verified; whether the app then runs is tested on every restore and reported, not promised.

Renest is for the moment after something works: a ComfyUI workflow producing the image you wanted, or a fine-tuning run (kohya_ss, LLaMA-Factory) that finally trained. It captures what that success depended on — models, custom nodes pinned to their commits, the dependency lock, the workflow or training config, the system libraries the run loaded — into a single open-format archive called a nest. Later, on a fresh pod, another region or another cloud, renest restore checks the machine first, brings every file back and checks it against its SHA-256, reinstalls the locked package versions, then starts the app, runs the workflow once and tells you what passed and what didn't.

System libraries belong to the machine, not the nest. A nest records which ones the run loaded and which image it ran on; on a machine that lacks one, the restore names it and the command to install it.

It does not try to make unfamiliar things work. It reproduces what already did.

• Website and docs: https://renest.ai · Quick start: https://renest.ai/docs/quick-start
• ComfyUI panel: https://github.com/renest-ai/comfyui-renest
• Format spec and the standalone restore.sh escape hatch: Apache-2.0. The CLI itself is source-available, not open-source software (see LICENSE-CLI).

Install

uv tool install --upgrade renest
renest --version

--upgrade matters if you have installed renest before: plain uv tool install renest treats an existing install as done and leaves the old version in place, so re-running it looks like an upgrade but is not. --upgrade moves an old install to the latest and is a harmless no-op on a fresh machine.

Python 3.11 or newer. No uv on this machine yet?

curl -LsSf https://astral.sh/uv/install.sh | sh
# Windows:  powershell -c "irm https://astral.sh/uv/install.ps1 | iex"
# only have pip?  pip install uv

On a proxy network, uv and curl read the proxy only from the environment, not from the OS/system proxy settings — so export HTTPS_PROXY=http://host:port (and ALL_PROXY) first, or the very first install step hangs with no error.

That last one is safe even inside the environment you are about to capture: uv is a single binary with no dependencies of its own, so installing it moves nothing else. That is not true of installing this package with pip.

Why uv and not pip. Two reasons, and the second one matters more than taste. First, rebuilding an environment is what this tool does, and it does it by calling uv — so does the escape hatch script inside every archive. A machine without uv can install this package and still not restore anything. Second, pip install renest installs into whatever environment is active, and that is often the very environment you are about to capture; resolving our dependencies there can move versions inside it. Protecting a setup that already works is the whole point of this tool, so we do not ask you to touch it to install us. uv tool install keeps the command in its own environment. pip install renest still works if you know your environment is separate.

Use

renest pack --dir /path/to/comfyui --workflow workflow.json --out ./nests
renest verify ./nests/<id>/manifest.json --dir /path/to/comfyui
renest restore --manifest ./nests/<id>/manifest.json --dir /path/on/the/new/machine
renest doctor

In order: capture a setup that already worked, check a rebuild end to end, rebuild it somewhere else, and ask whether this machine can. --dir is always the environment root — the folder holding ComfyUI/ — and every path is one you name, never one we guess.

renest --help lists the rest (list, lint, export, serve, presign, update-rules, support).

The escape hatch

Every nest ships with restore.sh, a plain shell script that rebuilds the archive using nothing but curl, jq, sha256sum, uv and tar. It does not import a single line of the rest of this project, and it is Apache-2.0 along with the format specification. If this project disappears tomorrow, your archives still open. That is the point of it, and it is why it is licensed the way it is.

The format specification lives in specs/ inside the wheel. Anyone can write their own reader from it.

One command exists purely for that day: renest presign signs a download link for an object in your own bucket, using keys that live on your machine. The escape hatch deliberately depends on nothing but curl, jq, sha256sum, uv and tar — it has no way to sign anything itself. So if this project is gone, the machine holding your storage keys is the one that can still hand out links, and that command is how.

Versions you will see

Five separate things carry their own version, because they change at completely different speeds:

• the tool — the version of renest itself
• the archive format — printed by renest --version; an archive records which one it was written with, and a newer tool reads every older one in the same major version
• the environment fingerprint — how a machine's shape is recorded
• the retrieval grant — how a time-limited download permission is written
• the local API — the endpoints under /api/v1 that a desktop or web client talks to

Plus a set of compatibility facts kept on your machine as data — things like which driver version a given CUDA release needs. Those are refreshed with renest update-rules without installing a new version of the tool.

Within one major version, things are added and never changed or removed. A breaking change moves to the next major version, and the old one keeps working alongside it.

Note that the tool's own version number is still 0.x, and the archive format's is not. That is deliberate, and the difference matters: the tool's command-line surface may still shift, but an archive written today stays readable. The format promise is the one your data depends on, and it does not move with the tool.

Licence — three layers, and they are not the same

Genuinely open (Apache-2.0): the archive format specification and the escape hatch script. These are the proof that you can open your own archives even if we are gone. Use, modify and redistribute them freely, with no conditions from us.

The ComfyUI plugin (GPL-3.0): it runs inside the ComfyUI process, so it follows that ecosystem's rules. It lives in its own repository.

This command-line tool — source-available, and not open-source software: the code is published in full. Read it, audit it, modify it for your own use, publish your modifications. The one thing not granted is using it, or a derivative of it, to offer other people a hosted service that competes with ours. The text is in LICENSE-CLI, which ships with this package.

It also carries a permanent exemption: any individual using it to pack, sign links for, restore or verify their own data may do so forever, unconditionally — this does not lapse because we shut down, because you have no account, or for any other reason.

In one line: the format and the escape route are public, the tool's code is open to read, and the only thing not given away is running a competing hosted service on it.

Links

• Source: https://github.com/renest-ai/renest
• ComfyUI plugin: https://github.com/renest-ai/comfyui-renest
• Compatibility data: https://github.com/renest-ai/renest-rules

The hosted service is operated by the author of this project.