Gab has been taken offline following revelations that the suspected Pittsburgh synagogue gunman used the social network to threaten Jews.
A statement on the platform's website Monday said it would be "inaccessible for a period of time" after several web hosting services declined its business.
Gab said it has also been removed from app stores and refused service by payment processing firms.
"Gab.com is under attack," the company said in the statement. "We have been systematically no-platformed [and] smeared by the mainstream media for defending free expression and individual liberty for all people."
The platform has come under scrutiny after it emerged that suspected gunman Robert Bowers frequently targeted Jews in his Gab posts, and even logged onto the platform shortly before allegedly killing 11 people at the Tree of Life synagogue.
Gab, which bills itself as "the free speech social network," said that it was working "around the clock" to restore service.
Gab is relatively small, but it has an avid user base. It was founded by entrepreneur Andrew Torba about two years ago. The site says it now has nearly 800,000 users, meaning that it's tiny compared to Twitter (TWTR) or Facebook (FB).
The site's claim to fame is that users can post almost anything — even if the content is racist — without being sanctioned. It puts nearly no restrictions on content.
Bowers' profile on the platform appeared to serve as an echo chamber for racist, anti-Semitic and bigoted ideology. The suspect reposted a number of posts on his social media accounts that tell Jews to get out, or leave.
Gab has denied supporting violence. It said it has backed up Bowers' profile data, suspended his account and contacted the FBI.
"We have been smeared ... for working with law enforcement to ensure that justice is served for the horrible atrocity committed in Pittsburgh," it said.
Gab said on Twitter that it has been banned from using payment processors Stripe and PayPal, as well as cloud hosting service Joyent and domain provider GoDaddy. It said online publisher Medium had also removed its posts.
PayPal (PYPL) confirmed that it would not allow Gab to use its platform to manage donations from users.
"When a site is explicitly allowing the perpetuation of hate, violence or discriminatory intolerance, we take immediate and decisive action," PayPal said in a statement.
Joyent, GoDaddy and Medium did not immediately respond to a request for comment. Stripe said it would not comment on individual users.