A free app with no advertising doesn’t make that kind of money, it gets progressively deeper into debt to a good Silicon Valley rich guy who got it off the ground, Brian Acton.

His biography on the Signal Foundation website:

Brian Acton is an entrepreneur and computer programmer who co-founded the messaging app WhatsApp in 2009. After the app was sold to Facebook in 2014, Acton decided to leave the company due to differences surrounding the use of customer data and targeted advertising to focus his efforts on non-profit ventures. In February of 2018, Acton invested $50 million of his own money to start the Signal Foundation alongside Moxie Marlinspike. Signal Foundation is a nonprofit organization dedicated to doing the foundational work around making private communication accessible, secure and ubiquitous.

Prior to founding WhatsApp and Signal Foundation, Acton worked as a software builder for more than 25 years at companies like Apple, Yahoo, and Adobe.

The Wikipedia article on the Foundation says the loan balance was up to $108M later in 2018. Meanwhile, Acton is still worth $2.5B according to Wikipedia, so things are probably fine for now, even 6 years later.

But you’re right that Signal eventually needs revenue to keep even a small team of high caliber software engineers and devsecops folks around. You very much want excellent engineers to continue to be involved with critical encrypted communications software on an ongoing basis, so it will cost money indefinitely. Presumably Acton does not wish to bankroll it indefinitely.

Again back to the interview:

I wouldn’t imagine that most nonprofits pay engineers as much as you do.

Yeah, but most tech is not a nonprofit. Name another nonprofit tech organization shipping critical infrastructure that provides real-time communications across the globe reliably. There isn’t one.

This is not a hypothesis project. We’re not in a room dreaming of a perfect future. We have to do it now. It has to work. If the servers go down, I need a guy with a pager to get up in the middle of the fucking night and be on that screen, diagnosing whatever the problem is, until that is fixed.

So we have to look like a tech company in some ways to be able to do what we do.

I’m really glad they pay those engineers that much, so that Zuckerberg and his ilk can’t entice them away with oodles of money. One presumes they also believe in the cause, but I think this currently looks like Acton fighting surveillance capitalism with what capitalism got for him earlier in his career.

Cofounder Moxie Marlinspike is clearly a brilliant hacker and coder who was crucial to Signal’s creation, but I think it makes sense that he hasn’t stuck around to try to solve the long term business problem of keeping it aloft infinitely.

So what to do about it? The OP interview is with Meredith Whittaker, who’s entire job is figuring that out:

Since she took on the presidency at the Signal Foundation, she has come to see her central task as working to find a long-term taproot of funding to keep Signal alive for decades to come—with zero compromises or corporate entanglements—so it can serve as a model for an entirely new kind of tech ecosystem.

I’m a recurring donor because I want Signal to succeed and I want to vote now with my wallet, but fundamentally it’s on Whittaker to figure out how to make the long term work. Here’s what she says:

I see Signal in 10 years being nearly ubiquitous. I see it being supported by a novel sustainability infrastructure—and I’m being vague about that just because I think we actually need to create the kinds of endowments and support mechanisms that can sustain capital-intensive tech without the surveillance business model. And that’s what I’m actually engaged in thinking through.