An invitation to tender (ITT) is the initial step in competitive tendering, in which suppliers and contractors are invited to provide offers for supply or service contracts, the ITT is one process in IT procurement.
An ITT document specifies all requirements of the organization, including goods, services and timelines, as well as the evaluation process that will be followed. Invitations to tender are often used by public sector organizations, which are legally obligated to offer contracts for goods or service requirements by that process in many countries.
In an open invitation to tender, any vendor who can provide a guarantee of performance may offer. In closed ITTs, vendors may have been preselected, screened or qualified by an expression of interest to generate a shortlist of eligible candidates. Often, proposals to a tender are under a double-envelope system, with separate technical and economical envelopes provided for individual evaluation by the inviting firm.
Invitations to tender are also known as calls for bids or calls for tenders.