Technology companies should use offer letters when extending offers of employment to potential employees.  The tech companies should not commit to fixed employment terms in the offer letters unless the intent is for the relationship to be other than at-will (in which case an employment agreement should be used).  Offer letters generally provide for the at-will nature of the employment and set forth other general terms and conditions of employment for protection of both the tech company and the employee.  Offer letters often refer to the tech company’s employment handbook.  With startup tech companies, offer letters are used much more often than employment agreements.