What is the CDX file format?
.cdx files are associated with CorelDRAW Graphics Suite, a vector graphics editing software developed by Corel Corporation. .cdx files store compressed .cdr drawings - CorelDRAW uses them to save vector graphics in a compact format, reducing file size compared to their uncompressed counterparts. Both share the same binary RIFF container, identified by the four-byte RIFF signature at offset 0 and an inner CDRx form tag.
.cdr images stored in compressed format (.cdx files) can easily be sent over email. .cdx archives are also used for storing image backup copies on external storage devices.
Today .cdx files are uncommon in new workflows. Modern CorelDRAW versions save .cdr documents that already include built-in compression, making the dedicated compressed variant largely redundant.
A practical caution: the .cdx extension is shared by several unrelated formats, most notably Visual FoxPro compound index files and ChemDraw chemical structure documents. Before treating a .cdx file as a CorelDRAW drawing, verify the originating application - the internal RIFF signature can help, but is not a reliable sole discriminator.
Security & safety
RISK: LOWA CorelDRAW .cdx is passive vector data with low risk. The practical caution is identity confusion: a file you assume is artwork may actually be a Visual FoxPro index or ChemDraw document. Only open .cdx files from sources you trust, and if your app rejects it, identify the true format (e.g. with a hex/file-type tool) rather than downloading dubious "CDX viewer" utilities, some of which are adware.
Format details
in a nutshell- Visual FoxPro / dBASE Compound Index - Native database index (.cdx) holding multiple ordered index keys with pointers into a .dbf table; the most widespread meaning of the extension.
- ChemDraw Exchange Document - PerkinElmer ChemDraw chemical-structure drawing in its CDX exchange format (also has a CDXML text variant).
- ConceptDraw PRO XML Document - Vector diagram saved by ConceptDraw PRO as a text/XML-based .cdx layout.
Programs that open CDX files
Windows2 apps
CorelDRAW
Paid File → Open and select the .cdx; CorelDRAW decompresses and shows the drawing. Re-save as .cdr or export to PDF/PNG. 
CorelDRAW Essentials / Standard
Paid Lower-cost CorelDRAW editions also open CorelDRAW .cdx drawings. 
macOS1 app
CorelDRAW.app (web)
Freemium Upload the .cdx to the browser CorelDRAW; works best for files from recent CorelDRAW versions. Technical details
deep spec| Container format | RIFF (Resource Interchange File Format), CorelDRAW CDR family |
| Encoding | Binary, little-endian |
| Magic bytes | 52 49 46 46 (RIFF) at offset 0; inner form tag CDRx/cdrx |
| Compression | Compressed payload; the defining characteristic distinguishing .cdx from the uncompressed .cdr |
| Encryption | None inherent to .cdx; optional password protection in newer CorelDRAW applies to .cdr, not .cdx |
| Typical file size | 50 KB to 20 MB; noticeably smaller than the equivalent uncompressed .cdr |
| Color model support | CMYK, RGB, and spot colors (vector-native); embedded bitmaps support up to 32-bit color depth |
| Maximum page dimensions | Vector-based; CorelDRAW pages up to approximately 45 m per side |
| Platform support | Windows (primary); macOS supported in older CorelDRAW versions |
| MIME type | application/x-cdx (primary); application/coreldraw (alternative) |
| Internal version tracking | Mirrors the originating CorelDRAW CDR generation (v8 through v2024 RIFF layout families) |
| Internal structure | RIFF chunks containing compressed vector objects, layers, text, styles, embedded bitmaps, and a preview thumbnail |
| Extension collision | .cdx is also used by Visual FoxPro compound index files and ChemDraw chemical structure documents (unrelated formats) |
| Relationship to .cdr | A .cdx is a .cdr with a compressed payload; identical RIFF container, same feature set, smaller on disk |
| Current usage status | Largely deprecated; modern CorelDRAW .cdr files include built-in compression, making the separate .cdx variant redundant |
| Released | 1990s (CorelDRAW, as a space-saving compressed variant of .cdr) |
| Latest version | Tracks the CorelDRAW .cdr version that produced it (RIFF/CDR generations) |
CDX conversions
Community Q&A
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