---
title: "File formats"
description: "The file types Ouro renders as interactive viewers, and how to write them"
date: "2026-09-28"
last_updated: "2026-09-28"
---

Ouro picks a viewer for each file from its extension. Upload a file with one
of the extensions below and readers see it drawn in place, on the file page
and wherever it's embedded, not only as a download.

Most of these are standard formats that your tools already write. A few are
open formats Ouro defines for computed results that have no common standard.
Any service, script, or agent that writes one gets the same viewer as Ouro's
own routes.

## Materials and chemistry

- [Crystal and molecular structures](/docs/developers/file-formats/structures): .cif and .xyz files, drawn as 3D crystals or molecules

- [Molecules](/docs/developers/file-formats/molecules): .pdb, .sdf, and .mol files, drawn as protein cartoons or ball-and-stick molecules

- [Volumetric data](/docs/developers/file-formats/volumetric-data): Gaussian .cube files, drawn as isosurfaces and slices of densities and potentials

- [Phase diagram](/docs/developers/file-formats/phase-diagram): Open .phasediagram format, drawn as an interactive convex hull

- [Band structure and DOS](/docs/developers/file-formats/electronic-structure): Open .bandstructure and .dos formats, drawn as band structures and densities of states

- [Phonons](/docs/developers/file-formats/phonons): Open .phonons format, drawn as phonon dispersions with the density of states

## Engineering and design

- [3D models](/docs/developers/file-formats/3d-models): .glb, .stl, and .obj files, drawn as rotatable 3D models

- [KiCad schematics](/docs/developers/file-formats/kicad): .kicad_sch files, drawn as circuit schematics

## Diagrams and interactive pages

- [Mermaid diagrams](/docs/developers/file-formats/mermaid): .mermaid and .mmd files, drawn as flowcharts, sequence diagrams, and more

- [HTML pages](/docs/developers/file-formats/html): .html files, rendered as live pages with scripts and theme support

## Everything else Ouro previews

These need no special preparation, so they don't have their own pages.

| Kind             | Extensions                                                         |
| ---------------- | ------------------------------------------------------------------ |
| Images and media | Images, `.svg`, video, and audio                                   |
| Documents        | `.pdf`, `.md`, `.mdx`                                              |
| Tables and data  | `.csv`, `.xy`, `.xye`                                              |
| Code             | `.py`, `.ts`, `.json`, `.yaml`, `.sql`, and other common languages |
| Archives         | `.zip`, listed by contents                                         |

To request a viewer for another format, [let us know](/contact).