A recent survey by cloud platform provider Fastly found that senior developers are leveraging AI to do more coding, with 32% of those with 10 or more years of experience saying AI-generated code accounts for over half of their shipped code. In contrast, only 13% of junior developers (with fewer than 2 years of experience) report the same.
The survey, conducted from July 10 to July 14, 2025, gathered responses from 791 professional developers. Senior developers not only use AI more aggressively but also trust it more in production environments. This is surprising given growing concerns about "vibe coding" introducing vulnerabilities into code.
Despite potential drawbacks, 59% of senior developers say AI tools help them ship code faster overall, compared to 49% of junior developers. Additionally, 28% of developers fix or edit AI-generated code frequently enough to offset most of the time savings, while 14% say they rarely need to make changes.
Senior developers are better equipped to catch and correct AI mistakes, which may explain the gap in speed gains between senior and junior developers. Nearly 80% of all respondents said AI tools made coding more enjoyable, with some appreciating the ability to skip grunt work and others enjoying the dopamine rush of code on demand.
The survey also explored developer awareness of green coding, with 80% of mid- and senior-level engineers considering energy use in their work, compared to 56% of junior developers. Developers are also aware of the environmental cost of AI tools, with roughly two-thirds knowing that these tools can carry a significant carbon footprint.
