mmcif-tools in the browser

Run mmcif-tools (documentation) on your mmCIF files without installing anything. The tools run inside this page with Pyodide (Python compiled to WebAssembly): your files are read on your computer and are never uploaded.

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1. Open files

Choose mmCIF files (.cif or .cif.gz) or drop them here

2. Choose the tools

Same as the command line:

3. Result

Step	Command	Exit	Time	Output

What runs here

Each tool runs as on the command line (mmcif_selchain -A file.cif), and each step of the pipeline reads the output of the step before. Use ? to read a tool's help.
mmcif_fetch is not available: it downloads files, which Python cannot do inside the browser. Download the file from the RCSB or the AlphaFold DB and open it here.
mmcif_splitchain and mmcif_splitmodel write one file per chain or model: they must be the last step, and you download the files as a zip.
mmcif_merge, mmcif_mkensemble and mmcif_intersect read all the opened files, in the order of the list, and mmcif_frompdb reads a PDB file: they must be the first step. Tools that write something other than mmCIF (reports, tables, FASTA, PDB) must be the last.
Python in the browser is about 1.5 times slower than on your computer. Files of up to about 2.5 million atoms (250 MB) work; bigger ones get slow, and mmcif_sort and mmcif_assembly, which hold all the atoms in memory, can run out of memory (Python then restarts). For big files or many files, install mmcif-tools: pip install mmcif-tools.