Gemini 3.1 Pro vs Seed 1.5-VL

Gemini 3.1 Pro

Google DeepMind

Gemini 3.1 Pro is a multimodal language model from Google DeepMind, released in preview in February 2026 as a point-version upgrade to Gemini 3 Pro focused on improving reasoning depth, factual grounding, and coding and agentic task performance. The model accepts text, images, video, audio, and PDFs as inputs across a 1M token context window, extending the multimodal breadth of the Gemini 3 series with a companion endpoint specifically optimized for custom tool use in agentic pipelines. Google describes it as built to refine the reliability and performance of the Gemini 3 Pro series, reflecting an incremental engineering iteration rather than an architectural overhaul.

ByteDance

Seed1.5-VL, released by ByteDance Seed on May 15, 2025, is a vision-language foundation model composed of a 532M-parameter vision encoder and a Mixture-of-Experts language model with 20 billion active parameters. It was pretrained on over 3 trillion multimodal tokens and achieved state-of-the-art performance on 38 out of 60 public VLM benchmarks at release. Seed1.5-VL targets complex visual reasoning, OCR, video comprehension, 3D spatial understanding, and multimodal agentic tasks.