More than 800 startups and investors, organized by the incubator Y Combinator and the policy advocacy group Engine, are taking aim at the Federal Communications Commission over net neutrality.

On Wednesday the group sent a letter to the FCC protesting chairman Ajit Pai's proposal to unravel net neutrality rules, asserting that such changes would divide the internet by allowing larger companies to pay for faster delivery of web content while forcing smaller companies into slower lanes.

"We're deeply concerned with your intention to undo the existing legal framework," the companies, which include Warby Parker, Foursquare, and Etsy, wrote in the letter. "Without net neutrality, the incumbents who provide access to the internet would be able to pick winners or losers in the market."

Pai said the first step in the plan was to reverse the Title II classification of internet service providers. This would remove many regulations on big names like Comcast or Verizon and allow them to give special treatment to preferred news sites, streaming videos, or other online content. While all the details haven't been hammered out, the approach is a drastic change from the one taken by the FCC during the Obama Administration, which approved rules that ensured an open internet.

"Rather than dismantling regulations that allow the startup ecosystem to thrive, we urge you to focus instead on policies that would promote a stronger internet for everyone," the companies wrote in the letter.

There will be months of comments and revisions before a new policy can go into effect, but it is expected that any plan Pai puts up for a vote by the majority-Republican commission would pass.