Tilion raises $500,000 from Y Combinator for AI-agent browser infrastructure

Tilion has secured $500,000 from Y Combinator and joined its Fall 2026 batch, backing a browser business built for AI agents rather than people. The four-founder startup develops infrastructure for assistants that need to navigate websites and complete tasks such as booking tickets or filling forms, according to Daily Excelsior.

The product addresses a practical dependency: an AI assistant carrying out work online needs a browser that can load pages and keep operating without being blocked. A slow browser adds waiting time; a blocked one can prevent the assistant from finishing. Tilion’s stated aim is to make that browser work fast and reliable at scale.

Its browser engine is called Fortress. ET Edge Insights reported on October 15 that Fortress had reached 100,000 installations and that more than 170 companies used Tilion’s technology. Those are different measures: one counts installations of the engine, while the other describes company adoption. Neither figure is presented as a count of paying customers.

More than 170Companies using Tilion’s technology

ET Edge Insights reported this adoption figure alongside Tilion’s funding and accelerator participation.

Tilion’s competitive case also includes two named public evaluations. Daily Excelsior reports that it ranks first on ComputeSDK’s Browser Lifecycle test and BrowserArena’s latency leaderboard. ET Edge Insights describes those evaluations as comparing aspects of how quickly browser infrastructure can be brought into action and used.

Both publications place Tilion ahead of Browserbase in those tests. Browserbase announced a $40 million funding round in 2025 at a reported $300 million valuation, according to ET Edge Insights. That gives the comparison a clear financial contrast: Tilion’s reported speed rankings put it above a competitor with a much larger financing round.

The distinction is between speed in the named evaluations and the broader promise of dependable task completion. Tilion pitches both speed and reliability, but the benchmark descriptions concern how quickly browser infrastructure starts and operates. The rankings should be read within that scope, rather than as a verdict on every part of an AI assistant’s work.

Tilion was founded by Arman Luthra, Md Shahrier Islam Arham, Kazi Fardinul Hoque and Abdul Basit Tonmoy, who met in college. All four are now based in San Francisco. Luthra, the chief executive, leads product and sales; Arham is chief technology officer. Hoque and Tonmoy work on AI systems and research.

The founders have also co-authored published AI research. Their commercial division of labor pairs Luthra’s product and sales responsibilities with Arham’s browser engineering and Hoque and Tonmoy’s AI work. The Y Combinator investment and batch entry now give that team accelerator backing for its infrastructure business.