Less guessing.
More getting things done.
Meet your toolkit for everyday files. Learn the basics, connect tools into a workflow, or take OneKit to your terminal.
What is OneKit?
OneKit helps you compare, convert and process PDFs, images, documents, code and other files. Use a single tool for a quick task, connect tools for a repeated job, or run the shared Python core from your command line.
Your files. Your device.
Browser tools process your files on your device. Documents and results are not uploaded to our servers. OneKit downloads the processing environment and any needed packages, then reuses them while you navigate between tools.
- Choose a tool. Search the catalog or pick a category. Tools marked as in development for the browser are available through the CLI with their required engines.
- Add your input. Select files or paste text where supported. The selected file appears by name; use Replace or Remove to change it.
- Adjust and run. Preview and select PDF pages, drag to reorder them, or crop images visually. Download the result when processing finishes.
OneKit prepares its local environment in the background. Public downloads can be cached for future visits. Your working files are not stored in that cache. Cancelling an operation stops the processing environment.
What do ✓ and ≈ mean?
✓ Content preserving: the operation is designed to preserve the relevant content. ≈ Conversion with compromises: layout, fonts, metadata or detail may change. Hover or focus the symbol on a tool card to read its specific explanation.
How do comparisons and merging work?
Open two files or paste two texts. Additions appear in green and removals in red. Use the arrows on individual changed lines to apply either version to the other side, one change at a time. You can keep editing and download either side. JSON comparisons normalize keys; notebook comparisons can focus on code, Markdown or both.
What does a workflow do?
A workflow runs tools in order. The output of one step becomes the input of the next, so you can finish several tasks without repeatedly downloading and choosing files.
Remove a cover page, then rotate the remaining pages by 90°. Use a PDF with at least two pages. You can change both settings after opening this setup.
Compress an image, then convert the result to WebP. Image quality and file size depend on your input and settings; compression can lose detail.
Check whether a JSON document is valid and save the report. A workflow can contain just one tool; add more steps only when their input formats are compatible.
This is a setup example, not a live file operation. In the builder, choose Open workflow to load the downloaded .1kit file, then add your own files.
- Choose your starting file and first tool. Each step needs a compatible format and must stay within its own size limit.
- Add and configure steps. Expand a block to edit its options. Dragging a block changes its position on the canvas; steps run in their numbered order.
- Run once, then save. OneKit stops if a step fails. Save workflow downloads the tools, options and layout as a .1kit file; Open workflow restores them. Input files and passwords are excluded.
You can also run a saved setup from the CLI:
onekit pipeline --steps workflow.1kit input.pdf -o output/OneKit on your command line
The CLI uses the same processing core and supports the full tool catalog. Python 3.11 or later is required. Some tools also need optional packages or external engines such as FFmpeg, LibreOffice or Pandoc.
python -m pip install "onekit-tools[pdf,images,documents]"Discover and check
onekit list
onekit doctorTry a PDF merge
onekit run pdf-merge first.pdf second.pdf -o combined.pdfUse onekit doctor TOOL_ID to check the dependencies for a specific tool. OneKit preserves existing output files unless you deliberately pass --force. For passwords, use --ask-password to keep secrets out of shell arguments.
A toolkit you can inspect and improve
The OneKit Python core is open source under the Apache-2.0 license. Its code powers both the browser tools and the CLI. You can inspect the implementation, report a bug, suggest a tool or contribute a fix.
Explore the OneKit repository
Source code, tool definitions, tests and contribution guidelines, all in one place.
View on GitHub ↗Questions, limits and troubleshooting
What is a .1kit file?
.1kit is the OneKit file extension. A saved workflow contains its tools, options and canvas layout, so you can reopen or share the setup. It uses versioned JSON with a workflow type identifier. Your input files and passwords are excluded. Both the browser and CLI can open .1kit workflows; older JSON workflow exports remain supported.
How large can my files be?
PDF merge, split, page removal, organization, extraction, repair, rotation and unlock accept up to 100 MiB per file and in total in the browser. Other tools keep their own limits, shown in the file picker. Text tools generally allow 8 MiB, comparisons 2,000,000 bytes per file and fonts 16 MiB. The CLI has a 128 MiB batch ceiling, with lower per-tool limits. Images also have pixel limits. Complex files may need more memory than a phone can provide.
Why is a tool marked as in development?
It is not yet enabled in the browser. The CLI catalog includes it, but you must install its required dependencies or external engines. Use the tool’s CLI details page and onekit doctor TOOL_ID to see what it needs.
A workflow stops or a file is rejected. What should I check?
Check the actual file format, not just its extension, and the size limit shown for the selected tool. Each workflow step must accept the previous step’s output format and file count. A smaller-limit step cannot accept a larger result just because an earlier step supported it. Encrypted PDFs need the correct password. Try the step on its own to isolate the problem, or use the CLI for files beyond browser limits.
Can I close the tab or come back later?
Download your results before closing or refreshing. Working files and results live in the current session; reopening the site does not restore them. Save a workflow setup if you want to reuse its steps later, then choose the input files again.
How can I verify a download?
Use the versioned packages linked from the download page. They come directly from public GitHub Releases. Compare the file’s SHA-256 digest with the release manifest before installing. Optional native engines have their own platform requirements.
Does OneKit use analytics?
Optional Google Analytics loads only after you allow analytics cookies. You can change your choice using Cookie settings in the footer. File contents are not sent to Analytics. Read the privacy page for details.