Most companies using Startomatic are eligible.
There are a number of limitations on S-corporations; for example, they must have no more than 100 shareholders, all of whom must be individuals (i.e., not corporations, LLCs, or other entities), and none of whom may be nonresident aliens.
For more details, or to check to be sure your company will be eligible to make an S-election, visit https://www.irs.gov/instructions/i2553 to review the IRS's Instructions for Form 2553.