Open CKPT files in your browser
The checkpoints Stable Diffusion's first models and PyTorch Lightning came as. See what one holds right here, without running it. Nothing leaves your device.
Or drop it anywhere on this page
What you'll see
Your checkpoint opens as the model it holds, read without running any of it.
- Parameters, tensors and the size of the weights
- Every tensor in a table • Its type and shape
- Hyperparameters, epoch and step
- What loading it would call • Commands and code marked
About CKPT
A checkpoint is a model saved part way through its training or at its end. PyTorch Lightning saves them as .ckpt with the weights, the optimizer's state, the epoch and the hyperparameters, and Stable Diffusion's first models and the fine-tunes made from them were shared as .ckpt files.
Inside, a .ckpt is a PyTorch file: a pickle that names every tensor, with the weights beside it, zipped since PyTorch 1.6. Loading one in Python runs that pickle, which can do anything, so model sites moved to safetensors, which can only hold tensors.
Filepeek reads the pickle without running any of it, and never reads the weights. It shows the parameters, the tensors with their types and shapes in a table, the epoch, the step and the hyperparameters a Lightning checkpoint keeps, and every import loading it would call, with those that run commands or code marked.
Model checkpoint
.ckpt
Format
- MIME type
- application/octet-stream
- Made by
- PyTorch Lightning, among others
Inside the file
- Holds
- Weights, optimizer state and hyperparameters
- Format
- A PyTorch ZIP or pickle
- Saved by
- PyTorch Lightning and training scripts
- Runs code
- In Python, when loaded • Never here
Opens in every browser
Browsers download checkpoints. Filepeek shows what one holds in Chrome, Edge, Firefox and Safari, without running it.
- YouChromeOpens through Filepeek
- YouEdgeOpens through Filepeek
- YouFirefoxOpens through Filepeek
- YouSafariOpens through Filepeek
Apps that open CKPT
- WindowsComfyUI and Automatic1111 load Stable Diffusion's • PyTorch Lightning
- MacComfyUI and Draw Things load Stable Diffusion's • PyTorch Lightning
- iPhone and iPadDraw Things imports Stable Diffusion's
- AndroidNo app opens it
Questions
What is a CKPT file?
A model checkpoint: its weights, and often its training state, saved by PyTorch. Stable Diffusion's first models came as .ckpt, and PyTorch Lightning saves its checkpoints that way.
Is a CKPT file safe?
Opening it here is: nothing in it runs. Loading it in Python runs the pickle inside, which can do anything, so check what loading it would call first and load it only if you trust where it came from.
Why won't my TensorFlow checkpoint open?
TensorFlow names its checkpoints .ckpt too, but keeps them as an .index file and .data files of its own. Only PyTorch's open here.
Should I convert a CKPT to safetensors?
To share a model, yes: a safetensors file holds only tensors, so loading it can't run code, and Stable Diffusion's apps load either. Both open here.
How many parameters does my checkpoint have?
They're counted from the model's tensors, leaving out the optimizer's state, and show at the top with the size of the weights.