Blok Raises $7.5M to Revolutionize App Testing with AI-Powered User Simulations

Blok is using AI personas to simulate real-world app usage

AI-powered coding tools like Cursor, Replit, Claude Code, and Lovable are helping developers write many lines of code every day to ship products faster. However, app makers still have to rely on either shipping full beta versions of their apps or using simulation software to gauge how upcoming features will work. Blok, a company that is coming out of stealth, allows developers to use AI to simulate different user personas to test an app's features and learn how to make their apps better. The company was founded by Tom Charman and Olivia Higgs in 2024. Both have been serial entrepreneurs and worked on startups together as well in areas including travel and learning. To date, the startup has raised $7.5 million across two rounds. Its seed round of $5 million was led by MaC Venture Capital, with participation from people working at Discord, Google, Meta, Apple, Snapchat, and Pinterest. Blok's pre-seed round was with Protagonist with participation from Rackhouse, Ryan Hoover's Weekend Fund, and Blank Ventures. Marlon Nichols, Managing GP at MaC Venture Capital, said that Blok is often compared to Otptimizly and Amplitude, but those tools are more reactive. He said that Blok is edging them out by providing a predictive layer of testing for apps. "We backed Blok because we believe product development is at an inflection point. Teams are shipping faster than ever, but they're still making critical decisions based on A/B tests and gut instinct. Blok's simulation engine flips that model -- giving teams the ability to predict user behavior before a single line of code is written," he told TechCrunch over email. Higgs said that the need for testing is increasing as the complexity of interfaces has increased over time. She mentioned that they interviewed more than 100 product engineers to understand problems faced by product teams. "There is a real need for increased testing because the bar for visual interfaces is getting a lot higher. We're seeing people interact with technology through chat, through voice. So if you're introducing visual UI [elements] into the mix, you have to make sure that you are not introducing unnecessary friction into a user's workflow," she said. Charman said that both big and small companies face different problems. While small companies don't have cohorts to test out their products and get live feedback, big companies want to avoid stuffing features into their apps and making them clunky. "We are trying to reach a place where companies don't need to release their features on an experimental basis and wait for a few weeks or months for results to show up," he said. When a customer starts working with Blok, they upload their event log data from Amplitude, Mixpanel, or Segment. Blok then performs behavioral modeling and creates different user personas for app makers to test. These personas would roughly cover most of an app's user base. Then the development team submits a Figma design and experiment details -- including the hypothesis they want to test and the user goal they want to achieve -- to Blok, and the user persona agents then try to run the simulation many times. At the end, Blok will show insights about how users would use a particular feature and give recommendations. These insights include an overall report of the experiment and details about what went well and what could be improved. Teams can also look at a persona-wise report and suggestions. Plus, since it is 2025, there is a chatbot that you can ask queries to about your experiment. Blok has put its product behind a waitlist and is working with an initial set of customers, largely developing solutions in finance and healthcare. The startups said that these areas are ideal to target as they can't put out bad experiments in public and play around with the product a lot. The startup charges companies through a SaaS model, but it is also figuring out how to balance out compute costs. The company is aiming to hit mid-single-digit millions in revenue this year and open up to more customers.

Blok raises $7.5M to build AI agents that simulate human behavior to accelerate software testing

Blok raises $7.5M to build AI agents that simulate human behavior to accelerate software testing A startup called Blok Intelligence Inc. today said it has raised $7.5 million to transform the software testing process with artificial intelligence agents that simulate the behavior of human users. The money comes via a seed funding round led by MaC Venture Capital, with participation from angel investors at companies that include Google LLC, Apple Inc. and Meta Platforms Inc. There was also an earlier pre-seed round led by Protagonist and backed by Rackhouse, Weekend Fund and Blank Ventures. Blok says it has developed AI agents that are grounded in a combination of behavioral science and product data to try to simulate how different types of people use software. That way, developers can identify the most useful features and uncover and eliminate any friction points in their applications. It's aiming to transform the software testing process, which often takes weeks, and condense it into a matter of hours. According to the startup, the capabilities its AI agents provide are needed more than ever, given the surging popularity of "vibe coding," where developers accelerate their productivity with the help of generative AI programming tools. That has led to a flood of new digital products, but the challenge is that many of these new applications aren't giving people what they want. To understand what users want from their software, companies will put new applications and features through a rigorous testing process. But that involves getting different humans to explore new products manually, and those teams cannot keep up with the pace at which new software is being created. Blok gets around that with AI agents that behave like humans. It says they're curious, imperfect and full of nuance, just like people are. By grounding them in the "messy realities" of human decision making, they're better able to identify what humans will like and dislike about new software products. Co-founder and Chief Executive Tom Charman (pictured, left, alongside co-founder Olivia Higgs) said he thinks static, one-size-fits-all software products are soon going to become obsolete, replaced by tools that are more adaptive and responsive to each user's needs. But developers need help to understand what those needs are. "We're already seeing teams drowning in data signals, slow feedback cycles and resource constraints," he said. "Product decisions fall back on charisma or the highest paid person's opinion. We're building a new model for the software of tomorrow that can make sense of complex data patterns at AI-scale." The CEO said early adopters of its platform in the financial services and consumer health industries are already using its platform to condense four- to six-week test cycles into a similar number of hours. Armed with the rapid insights it provides, those customers can make much bolder bets on product design, Charman added. MaC Venture Capital Managing Partner Marlon Nichols said Blok is tackling a critical challenge in modern software development. "It's leveraging AI to understand user behavior with enough precision to power real time adaptive experiences," he said. "Blok is creating the foundational AI infrastructure for the next generation of intelligent, user-centric software."