The tech community has added its voice to the debate around whether companies are at risk from an over-reliance on a cloud-based computing service run by e-commerce giant Amazon.

Financial News this week published an article that revealed Amazon Web Services as the predominant cloud provider to the City and highlighted concerns aired by the Financial Stability Board that the cloud computing giant could now be 'too big to fail'.

Responding to the article on Hacker News, the discussion forum of Y Combinator — the biggest startup accelerator in the US that has backed companies such as Dropbox and Airbnb — tech experts expressed their fears about the dependence on Amazon's offering.

“If you wanted to blow something up to make the west suffer, an AWS data centre would probably be a pretty good target. I wonder at what point that becomes a legitimate national security concern,” one contributor called Peteretep wrote.

Another, with the username Dalbasal, said: “It seems reasonable to start worrying about the fragility potentially introduced by these massive internet infrastructure companies.”

Amazon’s cloud service, which counts movie platform Netflix among its customers, has become the predominant provider in the City since it relaunched in 2006. Its customers include banking giants Citigroup, JPMorgan and HSBC. It also serves Nasdaq, 100% of the Fortune 50 companies, and the UK’s Financial Conduct Authority.

It is unclear, however, how many institutions rely on AWS, which is a risk, web developers on Hacker News pointed out. User Mgkimsal said: “How many government [and/or] university systems would be unable to function because of direct or indirect dependencies on AWS-related services? [Amazon] going down for, let's say four days, would cause big havoc on so many projects and systems I know of. I'm pretty sure most people have no clue how much of their data and systems functionality is reliant on AWS-related services.”

Fenwick67 added: “If AWS went down hard, it would be more than just ‘I can't watch Netflix’. Some people wouldn't be able to do their computer work, send receive emails, others might not receive their paychecks or be able to pay bills.”

Amazon insists that its services are safe. Gavin Jackson, head of Europe, the Middle East and Africa at Amazon Web Services, told FN that AWS has data centres in multiple counties and regions across the world and that clients can replicate data in different centres to ensure it is safe. “I can pretty confidently say that I don’t think that there’s any other company on the planet that has as many people thinking about security every day.”

However, critics say that nobody is immune to outages and point to the problems when an AWS S3 outage in February 2017 shut down a number of sites, including Business Insider, Quora, Medium and even AWS’ own dashboard, for several hours.

The Financial Stability Board said in a report entitled Financial Stability Implications from FinTech, published on June 27, that third-party service providers are "quickly becoming more prominent and critical, especially in areas of cloud computing and data services" and urged local regulators to explore whether tougher rules are needed.