Superhuman measures product-market fit by asking users how they would feel if they could no longer use the product; at least 40% should answer "very disappointed." Superhuman founder Rahul Vohra built a survey-based engine around that question to automate the measurement.
What is your product-market fit?
Startup entrepreneur and investor Marc Andreessen has defined product/market fit as “being in a good market with a product that can satisfy that market.” Reaching product/market fit means that you’re familiar both with your customer base and with the major needs and problems they have.
How do you find product-market fit for a startup?
Achieving product-market fit should be one of the foremost goals of your startup’s product team. It’s an essential quality that startup investors will look for. Conversely, the path to startup success is lined with failed companies that struggled to reach product-market fit.
What is UX in product-market fit?
User experience (UX) refers to how customers interact with your products and services, and the experience they have while doing so. In order for users to love your product, it must fulfill UX criteria such as:
- Useful (meeting your audience’s needs)
- Usable (efficient and easy to use)
- Findable (able to be discovered by your target audience)
- Credible (trusted by customers and experts)
- Desirable (with an attractive brand and design)
- Accessible (able to be used by a wide range of people)
- Valuable (clearly defining the benefit you receive)
There are several different UX metrics to measure product/market fit. One common heuristic, from Sean Ellis and described in First Round Review, is to measure the percent of users who would answer “very disappointed” if they could no longer use the product. When you ask users “How would you feel if you no longer had access to this product?”, at least 40% of users should respond “very disappointed.” After benchmarking nearly a hundred startups, Ellis found that companies that struggled to find growth almost always had less than 40% respond that way, while companies with strong traction almost always exceeded it.
How does Superhuman find product-market fit?
Rahul Vohra founded Superhuman, an email app built around speed. For example, the app offers dozens of keyboard shortcuts to help users search, label, filter, and send messages more quickly. In 2025, Grammarly acquired the email client and then renamed itself Superhuman, according to TechCrunch.
Superhuman built a product-market fit engine to automate the process of measuring product-market fit. This included:
- Conducting UX surveys among the app’s users
- Separating users into customer segments based on their responses
- Analyzing the collected data
- Making changes based on this analysis and tracking the results
This automated approach to product/market fit can help startups identify hidden insights and gaps in their knowledge. For instance, your company may actually be targeting users who aren’t as enthusiastic about your product as the “true customers.”
In particular, Superhuman encourages startups to focus on their so-called “high-expectation customers” (HXC). These individuals are the ideal customer for your business that you might imagine when you close your eyes. Think about questions such as:
- Which type of people most needs my products and services?
- Why is your product important to these people, and how will your product help?
- What kind of experience do you want people to have with your product?
Superhuman is just one startup that has excelled at reaching the right product/market fit. For more advice and best practices, get in touch with your connections in the startup community.
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Frequently asked questions
How does Marc Andreessen define product-market fit?
As "being in a good market with a product that can satisfy that market," according to the post. Reaching it means knowing your customers and their major needs and problems.
What is Superhuman's product-market fit engine?
It runs UX surveys among users, separates them into segments based on their answers, analyzes the data, then makes changes and tracks the results.
Who are high-expectation customers?
Superhuman calls them HXC: the ideal customers you picture when you close your eyes. The post suggests asking who most needs your product, why it matters to them and what experience you want them to have.
Which UX criteria matter for product-market fit?
The post lists seven: useful, usable, findable, credible, desirable, accessible and valuable.
