.ai File Extension

What kind of file is an .ai?

An .ai file is editable artwork saved in Adobe Illustrator's native format. It commonly contains vector paths, text, placed images, colors, layers, and one or more artboards. Adobe recommends keeping the AI master while a design is in progress because exported formats may not retain every Illustrator feature.¹

The suffix covers more than one internal structure. Older Illustrator files can be PostScript-based. Modern AI files are PDF-based and may include Illustrator-specific editing data. If Create PDF Compatible File was selected when saving, the file also carries a PDF representation that other Adobe applications and some third-party tools can use.¹²

Check the contents when compatibility matters. A PDF-compatible AI file normally begins with %PDF- (25 50 44 46 2D in hexadecimal), while older PostScript-based artwork commonly begins with %!PS-Adobe (25 21 50 53). The .ai suffix alone proves neither structure. Its historical MIME association is application/postscript, but modern artwork should not be assumed to be an ordinary PostScript program.

How do I open an .ai on my computer?

Adobe Illustrator on Windows or macOS is the safest choice when you need all editable features. Adobe lists AI separately from PDF, EPS, and other supported formats, and lets you choose an Illustrator-version compatibility target when saving.¹³

Other options depend on the file's contents:

• Inkscape on Windows, macOS, or Linux can import many modern AI files through their PDF representation, but Illustrator-only data and some effects may not survive.²
• A PDF viewer may display the PDF representation when the file was saved as PDF-compatible. It will not expose native Illustrator editing features.
• Ask the sender for PDF or SVG if you only need to review or reuse the visible artwork.

Missing fonts, linked images, plug-in effects, and features introduced in a newer Illustrator version can change the result. Keep the original file and inspect an exported proof before approving production artwork.

Poly support for .ai

Poly stores, syncs, shares, versions, and downloads .ai files, and you can find them by filename. Poly does not currently infer an Illustrator or PostScript format from the .ai suffix, create artwork thumbnails, preview the file, index embedded text or vectors, or make its contents available to the Poly agent.

For review and content-aware use in Poly, export a trusted copy as PDF. Keep the .ai original alongside it as the editable master.

History of .ai

Adobe cofounder John Warnock conceived Illustrator, and the first public release shipped on March 19, 1987.⁴ Early Illustrator artwork grew from Adobe's PostScript technology. As the application evolved, the native format moved toward a PDF-based structure with private Illustrator editing data, giving compatible software a view of the artwork without reproducing Illustrator's full editing model.²

This history explains why an .ai file might resemble PostScript, open as PDF, or require Illustrator. The filename alone does not identify its generation or capabilities.

Working with .ai and alternatives

Choose an output for the next step rather than treating one format as universal:

Package required fonts and linked assets when licensing permits, or embed links before handoff. Treat unexpected legacy AI files cautiously because PostScript is executable input. Open untrusted artwork only with maintained software and avoid unrestricted conversion tools.⁵