August 6, 2025
5 min read
Lee Chong Ming
Vercel's CEO says AI agents are becoming software's primary users, reshaping APIs and developer tools for an AI-first future.
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, explains how AI agents are becoming the primary users of software, fundamentally reshaping how APIs and developer tools are designed. The future of software isn't being built for people — it's being built for machines, said Vercel's CEO, Guillermo Rauch. "Your customer is no longer the developer," Rauch said during an episode of the "Sequoia Capital" podcast published Tuesday. "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 shift where code is increasingly written not just for humans to read or interact with, but so AI agents can understand, use, and extend it. "That is actually a pretty significant change," Rauch noted. "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 means software tools will need to evolve based on how large language models (LLMs) interact with them. "LLMs' strengths and weaknesses will inform the development of runtimes, languages, type checkers, and frameworks of the future," Rauch said. He also highlighted that Vercel's newer users — who might not be developers but designers, marketers, or even AI agents — expect software to just work seamlessly. "Developers were used to dealing with errors and terrible, negative feedback all day long," Rauch said. "But today's users have a much shorter fuse when something goes wrong." Still, he views this as an "amazing pressure" for product builders. "You want something that works 99.99% of the time," he added. Last year, Vercel raised $250 million in a Series E round led by Accel, with investors including Tiger Global and GV.Rise of AI agents
The year 2025 has been hailed as the year of AI agents. These agents could fundamentally change how the internet works and how apps and software interact with users. Bernstein analysts wrote in February that while websites and apps won't disappear, users may no longer interact with them directly. Instead, they will access information, content, and widgets through an AI assistant that acts as "the aggregator of the aggregators." "If it scales and plays out like we think it might, this. Changes. Everything. The aggregators get disaggregated, and much of consumer internet may be structural shorts. Welcome to the Agentic AI era," the analysts wrote. "There's nowhere to hide." However, AI agents are not perfect. Researchers have warned that agent errors are prevalent and compound with each step they take. "An error at any step can derail the entire task. The more steps involved, the higher the chance something goes wrong by the end," wrote Patronus AI, a startup that helps companies evaluate and optimize AI technology. Patronus AI built a statistical model showing that an agent with a 1% error rate per step can compound to a 63% chance of error by the 100th step. Still, they noted that guardrails — such as filters, rules, and tools to identify and remove inaccurate content — can help mitigate error rates. Small improvements "can yield outsized reductions in error probability," Patronus AI said.Originally published at Business Insider on August 6, 2025.