UNIX® Certification Program

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UNIX® system certification guarantees compliance with Single UNIX® Specification, a set of open, consensus specifications that define the requirements for a conformant UNIX® system. The standardized programming environment provides a broad-based functional set of interfaces to support the porting of existing UNIX® applications and the development of new applications. The environment also supports a rich set of tools for application development.


Certification provides a formal recognition of product’s conformance to the Single UNIX Specification.

  • Suppliers are able to make and substantiate clear claims of conformance to the standard
  • Buyers get assurance that products they procure conform and will interoperate

Certification applies to a product or product family marketed by a supplier and means that a configuration matching a particular product standard will be delivered in full. Under the program, vendor guarantees conformance of its product to the Single UNIX Specification. This guarantee ensures that for the life of the product’s registration, the product remains conformant through fixes, enhancements and performance improvements, and any non-conformance will be fixed within a prescribed timescale. All current products are listed in the Register of Certified Products.

Product Standards

The UNIX® Certification Program is based on a series of product standards documents, which contain the conformance requirements for discrete areas of the technology. Product standards provide mapping between certification, the specifications, and the test suites needed to demonstrate conformance. The detail the technical conformance requirements, specific testing requirements, and is applicable, migration information from previous versions of the product standard.

Major product standards within the UNIX Certification Program include: UNIX 03, UNIX 03 Server, UNIX 98, UNIX 98 Workstation, UNIX 98 Server, UNIX 95, Common Desktop Environment (CDE), Motif, X Window System.


The objective of The Open Group UNIX 03 certification program is to encourage and facilitate the development and market availability of products that meet the Single UNIX Specification, Version 3. The Test suites and test procedures have a dual role in this context: first, they help developers and quality assurance teams to ensure the product meets the specifications and, second, they are used to ensure that only the eligible products are marketed as compliant.

The UNIX 03 Product Standard is built out of the following subsidiary product standards:

  • Internationalized System Calls and Libraries Extended V3
  • Commands and Utilities V4
  • C Language V2
  • Internationalized Terminal Interfaces

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