ProtonMail has accused Google of hiding the company from search results in what may have been an attempt to suffocate the Gmail competitor.
The free encrypted email service, which caters to nearly one million users worldwide, has enjoyed an increasing user base and popularity over the past few years as governments worldwide seek to increase their surveillance powers.
However, the growth of the company was severely impacted when, without warning, ProtonMail vanished from Google search results -- for 10 months.
In August, ProtonMail sent a number of vague tweets to Google, accusing the company of "intentionally hiding ProtonMail from search results," and even if unranking was unintentional, ProtonMail said it had proof that there was a "major bug" and "all previous contact attempts have been ignored."
According to the secure emails provider, Google hid ProtonMail from search results for queries including "secure email" and "encrypted email" -- a change which the company deemed "highly suspicious."
Between the beginning of summer and the fall of 2015, ProtonMail released ProtonMail 2.0, went open-source, launched mobile apps in beta, and changed domains from .ch to .com, which is more likely to appear in search results.
Together with a boost in users which pushed ProtonMail from half a million to the best part of one million users, this should have improved the company's search results.
However, by November, ProtonMail realized something was wrong. After consulting SEO experts, the firm found that there was an anomaly which was limited to Google searches and did not impact other services, such as Yahoo! or Bing.
With all other major search engines, ProtonMail's rankings sent them to page one or two for the terms "secure email" or "encrypted email," but when it came to Google, there was nothing.
In the early part of 2016, ProtonMail tried in vain to get in touch with Google, going so far as to contact Google's president of EMEA Strategic Relationships.
Around the same time, in April, European regulators were taking Google to task for allegedly reducing the ranks of competing companies. As ProtonMail is an email rival, this news was concerning.
It was August by the time communication channels opened, prompted once ProtonMail users and the company itself took to Twitter to complain. Google eventually responded -- saying little more than the company had "fixed something."
As shown in the image above, once Google issued a "fix," ProtonMail's search ranking immediately recovered. Now, the company is ranked at number one and number three for the search terms at the heart of the situation. ProtonMail said:
"Without any additional explanation from Google, we may never know why ProtonMail became unranked. In any case, we do appreciate Google finally taking action to resolve the issue, we just wished it happened sooner."
ProtonMail says the battle highlights what it calls "Search Risk" -- the reliance of companies on search engines which, if a relationship turns sour, can result in suppression or even force the closure of a business.
The company says that due to Google's alleged meddling, growth rates worldwide were reduced by at least 25 percent over the course of 10 months, which in turn sliced income from users by a quarter.
ProtonMail claims that this put financial pressure on the email provider and, instead of being able to manage monthly expenses comfortably, the company was forced to turn to emergency funds just to stay afloat.
In total, ProtonMail believes that the removal from Google ranking resulted in losses reaching several hundred thousand dollars, of which ProtonMail will never recover.
"The more we get the word out about the importance of online privacy, the more we make it impossible to suppress, ban, or otherwise pressure encrypted email services such as ProtonMail," the company says. "We believe online privacy is critical for an open, democratic, and free future, and regardless of the obstacles ahead of us, we will continue building the tools necessary to protect this future."
ZDNet has reached out to Google and will update if we hear back.