EOI meaning in Messaging ?

An invitation to tender (ITT, otherwise known as a call for bids or a request for tenders) is a formal, structured procedure for generating competing offers from different potential suppliers or contractors looking to obtain an award of business activity in works, supply, or service contracts, often from companies who have been previously assessed for suitability by means of a supplier questionnaire (SQ) or pre-qualification questionnaire (PQQ).

The term "notice inviting tenders" (NIT) is often used in purchasing in India.

An ITT differs from a request for quotation (RFQ) or a request for proposal (RFP), in which case other reasons (technology used, quality) might cause or allow choice of the second best offer. An RFP is a request for a price from a buyer but the buyer would also expect suggestions and ideas on how the project work should be done. RFPs are thus focused on more than just pricing/cost, they entail a bit of consulting from the contractor or vendor. The closest equivalent to an ITT in the mainstream private sector is an RFP which, since public money is not involved, typically has a less rigid structure.