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CCI file: what it is and how to open it

Nintendo 3DS ROM. Here is what a .cci file contains, how to open one on any device, and a viewer that opens it right in your browser.

Open a .cci file hereChoose fileRead in your browser. Nothing is uploaded.

What the viewer shows

  • Whether the file matches the .cci signature
  • The first bytes as hex
  • A preview when your browser can display it

What is a .cci file?

A .cci file is a nintendo 3DS ROM. Its registered MIME type is application/x-nintendo-3ds-rom, which places it in the application or document family of formats.

CCI is a binary format: the contents are not readable text, so opening it in a text editor shows scrambled characters.

The same format is also saved with the extension .3ds.

CCI file format details

Extension.cci
FormatNintendo 3DS ROM
MIME typeapplication/x-nintendo-3ds-rom
CategoryApplication or document
Text or binaryBinary
File signatureNone fixed
Registered with IANANo
Other extensions.3ds

How to open CCI files

WindowsCCI files (Nintendo 3DS ROM) are made by specific software. The reliable way to open one is with the program that created it; a generic viewer will only show raw data.
MacThe same applies on a Mac: look for a Mac version of the program that makes CCI files.
iPhone and iPadPhones rarely open this type of file directly. The viewer above can show what is inside it without installing anything.
AndroidThe same applies on Android. The viewer above shows the first bytes of the file so you can confirm what it is.

Can you convert a .cci file?

TapToConvert does not convert CCI files. The usual route is to open the file in the program that made it and use its Export or Save as option.

CCI file FAQ

What is a .cci file?

A .cci file is a nintendo 3DS ROM, with the MIME type application/x-nintendo-3ds-rom.

How do I open a .cci file?

With the program that created it. The viewer on this page shows what is inside without installing anything.

Is a .cci file safe to open?

CCI files hold data rather than programs, but any file from an unknown source can be crafted to exploit the software that opens it. Keep that software up to date. The viewer on this page only reads the bytes and never runs anything.

What is the MIME type of .cci?

application/x-nintendo-3ds-rom. Web servers send this type so browsers know how to handle the file.

Is CCI a text or binary format?

Binary. Its contents are not readable as text.

File type facts come from the IANA media type registry, the mime-db project and the freedesktop.org shared MIME database.

Similar file types

Try MP4 to MP3, HEIC, merge PDF or compress video.