Many startups and larger tech companies have attacked the problem of building AI to code software. Now, another new player emerges from the shadows to throw its hat into the ring, with a mission to fix many of the problems that will arise in a world where humans and all those AIs are writing code together.

Tessl is building what it says is an "AI native" platform that developers and their teams can use to build and maintain software, and on Thursday it opened up a waitlist for those looking to try it out.

We say "is building" for a good reason: Tessl's product has yet to launch, and the plan is to have it ready early next year. But the London-based start-up is now speaking a little more publicly about what it's doing with some financial fanfare: Tessl has quietly raised $125 million across a seed round and a Series A, both being announced for the first time today. The latest round is led by Index Ventures, with Accel, GV, and Boldstart participating. GV (aka Google Ventures) and Boldstart co-led the seed round.

I now get confirmation from multiple sources that post-money valuation for Tessl is north of $500 million.

As you might guess, one reason why a company without customers nor a shipped product is getting this kind of attention from top-shelf VCs is because of who is building it.

Founder and CEO is Guy Podjarny, a sort of developer whisperer. His last startup was Snyk, a cybersecurity firm last valued at $7.4 billion in 2022. He was the CTO at Akamai, who he joined after the company acquired his first startup, Blaze, which specialized in speeding up the loading times of websites.

He's very, very good [at understanding] developer communities and building developer-oriented businesses," said Carlos Gonzalez-Cadenas, the partner at Index who led the investment. Podjarny is extremely visionary and introspective about his business, that article quoted Gonzalez-Cadenas as saying.

Podjarny said in an interview that the concept for Tessl arose from his experience at Snyk.

Snyk specializes in finding – and fixing – security vulnerabilities in code; Podjarny noted that a similar problem was growing more pressing with code and software interoperability in general–in part because the writing of code was expanding rapidly, driven by the increasing use of AIs to compose code and other kinds of software automatically.

"What is AI doing to software development? " he recalled asking himself. The answer was: speeding it up, but also creating much more of it automatically. The complexity and prospect of systems breaking would compound the process of maintaining and shipping updates to that code. This eventually has many bad implications for organizations-including their security, uptime, cost, and efficiency.

"The more that picture formed in my mind, the more I knew I would build this," he said.

The name Tessl, he said, refers to "tessellation," the way software and its underlying code fit into a neat, clean whole, rather than exist in a messy, overlapping jumble.

Podjarny was cagey about what applications or code might be built or maintained on Tessl. But it sounds like it will actually start small.

"We're not yet showing the whole strategy about what that is," he said about target applications or use cases. "I would say we're not starting with games. We're starting with relatively simple software that allows us to build an end-to-end system that's more manageable for LLMs to generate, and more manageable for humans to specify. And we'll evolve from there."

So basically, the idea of the new startup is that developers and their teams-generating possibly a product manager along with others who aren't coders-can give specifications to Tessl in natural language or code, and Tessl will write code back that matches those specifications.

Teams can test that code in a sandbox, where issues can be flagged and addressed, and can continue to modify specs as required. Then, Tessl can be automated to maintain that code to that specification. So if something else risks breaking because of the new code, Tessl will run remediation to identify and fix that.

It sounds like Tessl isn't being conceived as a walled garden. Podjarny says he's talking to others who have built or are building AI coding assistants, with the hope that work on the other platforms also will be maintainable using Tessl. It sounds like Tessl isn't being conceived as a walled garden. Podjarny says he is communicating with others who have developed or are developing AI coding companions that their work-also slated to be maintainable using Tessl.
This would mean, in theory, it could compete with the likes of Anysphere's Cursor and Poolside, GitHub's Copilot, Magic, Codeium, Augment, OpenAI, IBM and many more but could work with whatever a team uses.

The startup will start with Java, Javascript and Python, but will expand further over time, Podjarny added. One reason investors love the idea and are willing to back it is that extensibility. Maintaining code is "something that has a lot of signal as being important right now," said Gonzalez-Cadenas. "But he's building a system of record here," he added. "Once you do that, there is a variety of opportunities.".