Vercel: AI models go stale in 3 months, open-weight share hits 56%

Vercel's AI Gateway Production Index shows most tokens are spent on models available for under four months, while average token price fell 23.2% for a third straight month. Open-weight models now account for 56% of token volume but only 14% of spend.

• Average token price dropped 23.2%, the third consecutive monthly decline
• Open-weight models: 56% of token volume but just 14% of spend
• Open-weight share was 13% in April and 10% in December 2025
• TypeSafe AI's Jev called the fastest-adopted model in the index