321 AI models ranked on IFBench. Each row shows the model’s score next to its cheapest API price per 1M tokens where it has one, so you can weigh quality against cost.
Top model today
Grok 4.3 (xAI) leads at 83%, from $1.25 per 1M input.
Each labelled name links to that model’s page. Curated to the cost-efficiency frontier, top scorers and cheapest so labels stay readable; the full field is in the leaderboard table below (and via “select all”). Reasoning models (extended “thinking” before answering) carry a ring around the dot.
Prices are on-demand list rates. Enterprise commitments can be materially lower. Cost per task uses best-effort token usage.
Frequently asked questions
What is the IFBench benchmark?
IFBench (Ai2) tests how well models follow new, previously unseen verifiable output constraints such as word-count limits, required keywords or formatting rules that were not part of training. Scoring is fully programmatic: verifier functions check whether each response satisfies the constraint.
Which AI model scores highest on IFBench?
Grok 4.3 (xAI) leads with 83%, from $1.25 per 1M input tokens.
How many models are ranked on IFBench?
321 models carry a IFBench score. Scores come from Artificial Analysis; where a model has a live API price it is verified against LiteLLM and OpenRouter, and models with no current price are listed without one.
xAI
MiniMax
NVIDIA
Alibaba
Xiaomi
Amazon
DeepSeek
Google
OpenAI
Zhipu
Moonshot
Meta
Cohere