About Tessl

About Tessl

Tessl is pioneering spec-driven development: the future of software development.

Software development is undergoing its biggest shift since the invention of the compiler.

Spec-Driven Development reimagines how we build: intent is written in natural language and captured in specs, AI generates the implementation, and systems evolve themselves over time. The result is higher-quality software, built faster, by more people, with AI at the core.

This transformation from code-centric to spec-centric software starts with agents.

Agents are powerful, but today they’re unreliable. They rush to code before understanding the requirements, claim success prematurely, hallucinate open source APIs, and break features when adding new ones. Without guardrails, agents are fast but fragile, and unfit for production codebases.

Tessl’s products keep agents on rails and well-informed. Specs define the functionality agents need to build, and contain tests to verify their work. Specs also serve to distribute reusable knowledge to agents, preventing hallucinations and ensuring they apply the right practices. Overall, they focus developers on what to build, and help agents tackle the how.

The outcome: you get the speed of agentic coding, with the reliability of production software. Join us in reshaping how software gets made.