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Lightsage has raised USD $4 million in seed funding led by Nexus Venture Partners. The money will support its platform for software companies targeting AI agents.
The San Francisco startup is focused on what it calls Agent-Led Growth, which it uses to describe selling to software agents that can discover and use products on behalf of users.
Lightsage argues that coding agents such as Claude Code, Codex and Cursor are changing how software is found and adopted. Instead of a human buyer reading a website, comparing products and then starting a trial, an AI agent may select a tool, install a software development kit and begin using an application programming interface with little or no direct human involvement.
That shift is creating a new set of concerns for software vendors. Companies need to know whether an agent can find their documentation, choose the right tool, authenticate correctly and complete a task without failing at a technical step.
Lightsage's platform runs simulations to test how AI agents interact with software products and where those interactions break down. It examines how agents handle documentation, APIs, SDKs, command-line interfaces, MCP servers and agent skills, then identifies failure points such as poor discoverability, confusing instructions, authentication problems and faulty integrations.
The company also analyses real agent traffic, tracking what AI agents do when they visit websites or documentation pages and whether those journeys lead to product use. Customers can use the findings to adjust product design, documentation and workflows, then rerun tests to see whether outcomes improve.
Investor backing
Nexus led the round, which also drew support from operators in the developer software and AI sectors. Backers include former Salesforce Chief Technology Officer Steven Tamm, Postman Chief Executive Officer Abhinav Asthana, Apollo Chief Executive Officer Matt Curl, DocuSign President and General Manager of Growth Robert Chatwani, former GitLab Head of Growth Hila, Resend Chief Executive Officer Zeno, Firecrawl Co-Founder Eric, Daytona Chief Executive Officer Ivan, Tinyfish Chief Operating Officer Shuhao and Adam Frankl.
Jun Liang Lee, Chief Executive Officer and Co-Founder of Lightsage, said the company sees a broader change in online software buying behaviour.
"We are moving from an internet where AI tells people which software to use to one where AI increasingly uses the software itself," Lee said. "That changes what growth means. Visibility still matters, but the real test is whether an agent can understand your product and get to a successful outcome. We think every software company will eventually need to optimize for that journey to unlock Agent-Led Growth."
Early users
Lightsage is starting with developer software, where agent behaviour is easier to observe than in many other categories. Customers including Firecrawl, Reducto, Daytona, Rime and Tinyfish are using the platform to understand why agents prefer certain products, where integrations fail and how workflows change after updates to products or documentation.
One common use case begins when a coding agent repeatedly recommends a rival service. Lightsage then recreates the task across products and agents to determine whether the cause is visibility, documentation or the product experience itself.
Traditional analytics tools are not designed for this kind of environment, the startup said. Human customer journeys can often be tracked through search, clicks and sign-up flows, but AI agents may discover, evaluate and use a product without following those standard steps. That makes attribution harder and means usage can vary significantly between coding agents.
The platform currently supports Claude Code, Codex, Cursor, GitHub Copilot and OpenCode, along with other coding agents. The new funding will be used to expand Lightsage's evaluation, analytics, attribution and optimisation tools across APIs, SDKs, CLIs, MCP servers and agent skills.
Nexus said Lightsage is trying to build a new layer of software around machine-driven product discovery and use.
"The internet brought the economy online, with humans discovering, choosing and transacting through digital channels. That created an enormous marketing technology industry focused on understanding and optimizing the human journey," said Abhishek Sharma, Partner at Nexus. "AI is now shifting that agency from humans to agents, which can discover, evaluate and act on a customer's behalf. Lightsage is building the intelligence infrastructure for this new era of autonomous browsing, helping companies optimize for agent conversion, not just awareness."