derail.app

What It Is

Derail is an “AI Focus Agent” designed to help users filter distracting content in real time while browsing the web. Instead of simply blocking sites based on a fixed list, it asks users to describe their goal for the day, then uses AI to decide whether the content they visit aligns with that goal. For example, if you are studying math, entertainment sites or dog videos may be blocked, while a math lecture can be allowed.

Core Features

The product centers on goal-oriented webpage blocking: users can refine the blocking prompt, and also set whitelisted and blacklisted sites, combining AI semantic judgment with manual rules. It also supports recurring daily or weekly focus sessions, making it suitable for scheduling deep work, study, or breaks as a regular routine. On the model side, Derail routes requests to multiple models through OpenRouter and says it selects models based on cost and availability, with a preference for open-source models. However, it does not disclose the specific models used, accuracy levels, or how false positives are handled.

Pricing and Privacy

The website does not provide clear plans or pricing. In the FAQ, the developer says they currently cover inference costs themselves and have optimized the architecture to serve a relatively large number of users, so it currently looks more like a free tool. Its long-term business model, however, remains unclear. On privacy, the official statement says it “doesn’t monitor you, sell your data, or track your browsing history.” That said, because requests are processed via OpenRouter and model providers, the page does not explain exactly what content is uploaded, whether it is retained, or for how long. Privacy-sensitive users should still be cautious.

Pros and Cons

Its main advantage is that it is more flexible than traditional blocking tools: it can judge content relevance based on a user’s goal, and it supports prompts, whitelists, blacklists, and recurring schedules. The downside is limited disclosure: it does not state which operating systems or browsers are supported, whether an API is available, whether team management is supported, or how well it works with a Chinese interface and Chinese-language webpages. Dynamic model routing may also create consistency issues in outputs.

Who It’s For and Access from China

Derail is suitable for students, remote workers, creators, and others who need to reduce the distraction of “mindless browsing.” The website does not state how accessible it is from China. If it relies on OpenRouter or overseas model services, real-world stability may be affected by network conditions. Alternatives include traditional focus tools such as Freedom, Cold Turkey, StayFocusd, and LeechBlock.