Should websites and apps be cheaper now because of AI coding tools?
Some of the work, yes. All of it, no. The honest answer depends on which part of a project you are looking at, and the research on how much faster developers really are does not agree with itself.
What the evidence says
- Nearly everyone uses AI tools now. In the Stack Overflow Developer Survey 2025, 84% of respondents said they use or plan to use AI tools in their development process, and 51% of professional developers use them daily. Trust is lower: 46% said they distrust the accuracy of AI output, against 33% who trust it. The most common frustration, cited by 66%, was AI answers that are “almost right, but not quite”, and 45.2% said debugging AI-generated code is more time-consuming (Stack Overflow).
- On a small, well-defined task, AI can be much faster. In a controlled experiment, developers with GitHub Copilot completed a task, writing an HTTP server in JavaScript, 55.8% faster than those without. The authors note that the study does not examine the effects of AI on code quality, and that benefits may vary across tasks and languages (Peng et al., arXiv).
- On real work in large, familiar codebases, the picture is less clear. METR’s randomised trial with 16 experienced open-source developers working on 246 real issues found that, with early-2025 AI tools, tasks took 19% longer. The developers had expected a 24% speed-up, and afterwards still believed they had been sped up by 20%. METR says the result does not show that AI slows down most developers (METR, 2025). In February 2026 it said developers are likely more sped up now than in early 2025, but that its new data is only very weak evidence for the size of that change (METR, 2026 update).
- Speed and stability move in different directions. Google’s 2025 DORA report, based on survey responses from nearly 5,000 technology professionals, found that 90% use AI at work and more than 80% believe it has increased their productivity. It found a positive relationship between AI adoption and software delivery throughput, but AI adoption “does continue to have a negative relationship with software delivery stability”; 30% reported little or no trust in AI-generated code (Google Cloud). The report describes AI’s main role as “an amplifier, magnifying an organization’s existing strengths and weaknesses” (DORA).
Two lessons for a buyer. First, how much faster developers feel is not good evidence of how much faster they are. Second, faster code without strong testing and review tends to produce more incidents later, and you pay for those too. All figures above accessed 18 October 2026.