The following listing of a few general questions and answers about the InChI and the Trust is supplemented by an extensive technical FAQ available here.

Originally developed by the International Union of Pure and Applied Chemistry (IUPAC), the IUPAC International Chemical Identifier (InChI) is a character string generated by computer algorithm. It is a tool to be used in software applications designed and developed by those who choose to use it.

The InChI algorithm turns chemical structures into machine-readable strings of information. InChIs are unique to the compound they describe and can encode absolute stereochemistry making chemicals and chemistry machine-readable and discoverable. A simple analogy is that InChI is the bar-code for chemistry and chemical structures.

The InChI format and algorithm are non-proprietary and the software is open source, with ongoing development done by the community. A number of IUPAC working groups is currently creating standard for those areas of chemistry that are not yet handled by the InChI algorithm.

The InChIKey has been designed so that Internet search engines (such as Google, Yahoo, Bing, etc.) can search and find the links to a given InChI.

To make the InChIKey the InChI string is subjected to a compression algorithm to create a fixed-length string of upper-case characters. While the InChI to InChIKey hash compression is irreversible, there are a number of InChI resolvers available to look up an InChI given an InChIKey.

The InChI with its associated InChIKey is the only structure representation standard in the public domain, open-source and freely available to the scientific community.

InChIs and InChIKeys are used by scientists, publishers and database providers to enable web-based linking between sources of chemical content whether web-page, journal or magazine, or database.

Several very large databases already have implemented InChI and/or InChIKeys.

The most current InChI software release can be downloaded from the InChI Trust download page.

The InChI certification suite is a software package developed and designed to check that your installation of the InChI program has been performed correctly. The programs test your installation against a broad set of structures (which are provided with the Suite).

Once the programs are run and the results sent back to the Trust, an "InChI certified" logo will be sent to the respective person or organization. The InChI Trust certification logo can then be put on the pages of the web site for all users to see. The use of the InChI Trust certification logo is optional.

The cost of the certification suite is US $5000 per year. It can be purchased from the InChI Trust.

The InChI Trust is the not-for-profit organization created to maintain, enhance, promulgate, and freely distribute the InChI structure representation algorithm to the worldwide scientific community and to advise on its use.

The InChI Trust has been established to develop and support the current InChI standard and promote its uses to the chemistry community.

The Trust's goal is to enable the interlinking of chemistry and chemical structures facilitating the discovery of chemical science.

Membership of the InChI Trust helps support, shape and direct the Trust's ongoing development and maintenance of the InChI algorithm.

Members of the InChI Trust have the following benefits:

1. Attendance at the Annual General Meeting to discuss the direction and management of the InChI Trust, including the appointment of the Board of Directors.
2. Regular bulletins on the progress of the InChI and InChIKey.
3. Advice on implementation of the InChI code.
4. For vendors, inclusion in the Register of InChI-accredited implementers at no additional charge (provided the organization meets compliance requirements).
5. Complimentary copy of InChI Certification Suite.

The following conditions must be met to qualify for membership:

1. The Organization applying for membership should display InChIs or InChIKeys alongside their chemical information.
2. In an Organization with multiple divisions, the largest legal entity is considered the InChI Trust member and all divisions are subject to the terms of the InChI Trust membership agreement.

The InChI Trust is funded by member dues. The fee structure is as follows and is based on the annual turnover of the joining company.

Company Members: