SAN FRANCISCO — Parler, the social network that drew millions of Trump supporters before disappearing from the internet, is back online a month after Amazon and other tech giants cut off the company for hosting calls for violence around the time of the Capitol riot.

Getting iced out by the tech giants turned Parler into a cause celebre for conservatives who complained they were being censored, as well as a test case for the openness of the internet. It was unclear if the social network, which had positioned itself as a free speech and lightly moderated site, could survive after it had been blacklisted by the biggest tech companies.

For weeks, it appeared the answer was no. But on Monday, for the first time since Jan. 10, typing into a web browser returned a page to log into the social network — a move that had required weeks of work by the small company and that had led to the departure of its chief executive.

It was unclear how Parler had figured out how to host its site on computer servers, the central technology underpinning any website. Many of the large web-hosting firms had previously rejected it. For other services required to run a large website, Parler relied on help from a Russian firm that once worked for the Russian government and a Seattle firm that once supported a neo-Nazi site.

Parler’s return appeared to be a victory for small companies that challenge the dominance of Big Tech. The company had sought to make its plight about the power of companies like Amazon, which stopped hosting Parler’s website on its computer servers, and Apple and Google, which removed Parler’s mobile app from their app stores.

Parler had become a hub for right-wing conversation over the past year, as millions of people on the far right had flocked to the platform over what they perceived as censorship of conservative voices by Facebook, Twitter and Google. Much of the content on Parler was benign, but for months before the Jan. 6 Capitol riot, the site also hosted calls for violence, hate speech and misinformation.

Parler had more than 15 million users when it went offline. It is largely financed by Rebekah Mercer, one of the Republican Party’s biggest benefactors.