Even as President Putin tightened his grip on Russian society over the past 22 years, small pockets of independent information and political expression remained online.

The remnants are gone.

A digital barricade went up between Russia and the world as Mr. Putin waged war on Ukraine. The wall was built in breathtaking speed by both Russian authorities and multinational internet companies. The internet was once seen as helping to integrate Russia into the global community.

TikTok and Netflix are suspending their services in the country. The social networking site has been blocked. The future of YouTube is in doubt. Apple, Microsoft, and other companies have pulled out of Russia. There are no online video games anymore.

The actions have turned Russia into a walled off digital state like China and Iran, which tightly control the internet and censor foreign websites and dissent. China's internet and the Western internet have become almost completely separate over the years, with few overlap services and little direct communication. During protests in Iran, the internet has been blacked out.

The internet is a tool for democracy that would lead authoritarian countries to open, but Russia has left the internet.

Brian Fishman is a senior fellow at the New America think tank and former director of counterterrorism policy at Facebook. It has choke points.

The internet is only one part of Russia's isolation. The country has been cut off from the world's financial system, foreign airlines are not flying in Russian airspace, and global access to its oil and natural gas reserves is in question.

The digital cutoffs are the culmination of Russian authorities trying to control the internet. The war led multinational companies to take the final steps after years of trying to move toward what is known as a "sovereign internet."

Digital isolationism serves Mr. Putin's interests, even though Russia is paying a stiff economic cost for being cut off. It allows him to control dissent and information that doesn't follow the government line. Journalists, website operators and others are at risk of 15 years in prison for publishing misinformation about the war in Ukraine.

Alp Toker, director of NetBlocks, a London organization that tracks internet, said that this will feel like a return to the 1980s for people who lived in that era.

An associate professor at Dublin City University who specializes in digital rights in Eastern Europe said that internet censorship efforts in Russia have grown over the past decade. Mr. Putin began cracking down on government critics online. Russia began a campaign to block or slow down access to websites.

The final break since the invasion has jarred Russians who used the internet to stay connected with the wider world, get independent information and build their careers.

The man who quit his job on state television in the face of growing censorship said he felt a second birth when he started producing news shows. He and his team publish investigations and news reports that are not available on state media on his channel.

He said in a recent interview that he would never work as a journalist again.

The work could put Mr. Pivovarov in jail or out of business. Russian state television outlets were barred from being shown across Europe and all Russian accounts were blocked from making money from their videos on YouTube. Experts predicted that Russian regulators will block YouTube in the future.

Mr. Pivovarov said he would keep broadcasting on the internet despite the risks. He said it was not clear how long he could keep going.

He said that he plans to work in Russia for the moment.

Unlike China, where domestic internet companies have grown into conglomerates over more than a decade, Russia does not have a similarly vibrant domestic internet or tech industry.

The repercussions may be severe as it is isolated from the rest of the world. The future reliability of internet and telecommunications networks, as well as the availability of basic software and services used by businesses and government are at risk.

Russian telecom companies that operate mobile phone networks have lost access to new equipment and services from companies like Nokia. Taiwan Semiconductor Manufacturing Company halted shipments to the country after it halted shipments to Russia. Russia's largest internet company, with a search engine that is more widely used than any other in the country, warned it may default on its debts because of the crisis.

The entire hardware and software market that Russia relies on is gravely damaged right now, according to a researcher at the University of Oxford. He said that Russian authorities could respond by relaxing rules that make it illegal to download software.

The internet service providers in Russia have been pressured by the Ukrainian government. The Russian internet domain has been asked to be suspended by officials from Ukraine.

Russia's censorship campaign is devastating for those who grew up with a less restricted internet, according to a self-taught web developer with more than 15 years of experience.

I bought my first computer when I was 19 years old, and it was the best investment of my life, said Mr. Everyone could say what they wanted.

The company where Mr. Lyashkov worked received a demand from the government to install new government certificates on its website, a technical change that could allow regulators to monitor traffic and potentially close the country's internet to all but Russian. Russia took such a step last year.

Russian internet users appeared to be finding ways around restrictions. Demand for virtual private networks, technology that lets people access blocked websites by masking their location, soared more than 600 percent since the invasion, according to Top10VPN, a service that tracks usage of the technology.

Other decisions by multinational companies to punish Russia could make it harder to get circumvention tools. Visa and Mastercard have blocked payments in Russia for many Russians who use a virtual private network.

That move only helps the Kremlin, according to Mr. Pivovarov.

Kate Conger was involved in reporting.