August 6, 2025
5 min read
Lee Chong Ming
Vercel's CEO says AI agents are becoming software's next users, transforming how APIs and developer tools are designed and built.
An Accel-backed startup CEO says your next user isn't human — and it's changing how software gets built
Vercel's CEO, Guillermo Rauch, believes the future of software development is shifting from human users to AI agents. These AI agents are becoming the primary users of software, fundamentally reshaping how APIs and developer tools are created. "Your customer is no longer the developer," Rauch said on the "Sequoia Capital" podcast. "Your customer is the agent that the developer or non-developer is wielding." Vercel, a web infrastructure startup valued at $3.25 billion last year, is witnessing a paradigm shift where code is increasingly written not just for humans to read or interact with, but for AI agents to understand, use, and extend."That is actually a pretty significant change," Rauch explained. "Is there something that I could change about that API that actually favors the LLM being the, quote-unquote, entity or user of this API?"This AI-first era demands that software tools evolve based on how large language models (LLMs) interact with them. Rauch emphasized that the strengths and weaknesses of LLMs will influence the future development of runtimes, programming languages, type checkers, and frameworks. Moreover, Vercel's newer users—who might be designers, marketers, or even AI agents rather than traditional developers—expect seamless functionality. Rauch noted that while developers are accustomed to frequent errors and negative feedback, today's users have little patience for failures.
"You want something that works 99.99% of the time," he said. This pressure, Rauch believes, is a positive force driving product excellence.Last year, Vercel raised $250 million in a Series E funding round led by Accel, with participation from Tiger Global and GV.
Rise of AI agents
The year 2025 has been marked as the rise of AI agents, which could revolutionize how the internet functions and how users interact with apps and software. Bernstein analysts noted that while websites and apps will continue to exist, users may no longer interact with them directly. Instead, AI assistants will serve as "aggregators of the aggregators," providing streamlined access to information and services."If it scales and plays out like we think it might, this. Changes. Everything," the analysts wrote. "The aggregators get disaggregated, and much of consumer internet may be structural shorts. Welcome to the Agentic AI era."However, AI agents are not without flaws. Researchers warn that errors in AI agents are common and tend to compound with each step in a task. Patronus AI, a startup focused on optimizing AI technology, found that even a 1% error rate per step can lead to a 63% chance of failure by the 100th step. Despite these challenges, implementing guardrails such as filters, rules, and accuracy-checking tools can significantly reduce error rates. Patronus AI highlights that small improvements can yield outsized reductions in overall error probability.
This article is based on insights from Guillermo Rauch, CEO of Vercel, and analysis from Bernstein and Patronus AI.
Source: Originally published at Business Insider on August 6, 2025.