TWAIN is an applications programming interface (API) and communications protocol that regulates communication between software and digital imaging devices, such as image scanners and digital cameras.

TWAIN isn't a hardware-level protocol; it requires a driver called Data Source for each device.


The design of TWAIN began in January 1991. The TWAIN group originally launched in 1992 by several members of the imaging industry, with the intention of standardising communication between image handling software and hardware. Review of the original TWAIN Developer’s Toolkit occurred from April, 1991 through January, 1992.

The word TWAIN isn't officially an acronym, but it is a backronym. The official website notes that "the word TWAIN is from Kipling's The Ballad of East and West — '...and never the twain shall meet...' — reflecting the difficulty, at the time, of connecting scanners and personal computers. It was up-cased to TWAIN to make it more distinctive. This led people to believe it was an acronym, and then to a contest to come up with an expansion. None was selected, but the entry Technology Without an Interesting Name continues to haunt the standard." For example, the Encyclopedia of Information Technology lists "Technology Without an Interesting Name" as the official meaning of TWAIN.

Release history of the TWAIN API
VersionRelease dateChanges
1.0February 1992
  • Initial release
1.5May 1993
  • Performance enhancements
1.65 February 1996
  • Page-length detection
  • Buffer transfer
1.719 August 1997
  • Production scanning features
1.822 October 1998
  • Production scanning features omitted from v1.7 of the TWAIN specification
1.920 January 2000
2.022 February 2008
2.18 July 2009
  • Support for Windows 7 (32- and 64-bit)
  • Support for automatic colour detection
2.216 February 2012
  • Implemented self-certification and new mandatory features
2.321 November 2013
  • Improved clarity and removed ambiguity.


Objectives of the TWAIN Working Group and standard include:

  • Ensure image-handling software and hardware compatibility
  • Keep the specification current with the state of current software and hardware while maintaining backward compatibility
  • Provide multiple-platform support
  • Maintain and distribute a no-charge developer's toolkit
  • Ensure ease of implementation
  • Encourage widespread adoption
  • Open Source Data Source Manager
  • LGPL Open Source License
  • BSD Open Source Sample Application and Sample Data Source Application

Supported technologies

TWAIN provides support for:

TWAIN Working Group membership

Today the TWAIN standard, including the specification, data source manager and sample code, are maintained by the not-for-profit organisation TWAIN Working Group.

Board and associate members of the TWAIN Working Group include: