Wan 2.1

Wan 2.1 is the model that established Alibaba's Wan (Tongyi) series in the open-weight video-generation community. Alibaba open-sourced it in February 2025 as a family of four checkpoints — text-to-video at 14B and 1.3B parameters, and image-to-video at 14B in 480p and 720p — with a first-and-last-frame variant following in April. Architecturally it is a flow-matching diffusion transformer paired with Wan-VAE, a 3D causal autoencoder that encodes and decodes 1080p video of arbitrary length while preserving temporal continuity, and a T5 text encoder for multilingual prompts. The Wan technical report (arXiv 2503.20314) describes training on a curated corpus of billions of images and videos; the smaller 1.3B text-to-video model was deliberately sized to run in about 8 GB of VRAM on a consumer GPU.

All four checkpoints ship under the Apache 2.0 licence, weights included, so the model can be self-hosted or reached through third-party hosts — the Replicate offering in this registry is a WaveSpeedAI-accelerated image-to-video wrapper around those weights. On VBench, Alibaba reported a total score of 86.22 for the 14B model (86.67 quality, 84.44 semantic), and Wan 2.1 topped the public VBench leaderboard at release; Modelglass records those as the vendor's launch figures rather than an independent re-run and rates the rest of this entry's capability profile as a qualitative read. As an Alibaba model it is developed and hosted primarily in China, which can carry data-residency or procurement constraints for some buyers.

Wan 2.1 has since been succeeded twice, and the distinction matters when choosing a target to build against. Wan 2.2 (July 2025) is the direct open-weight successor — a mixture-of-experts redesign, still Apache 2.0 — and is the upgrade path where a host offers it. Wan 2.5 (September 2025) added synchronised native audio, 1080p output and ten-second clips but is API-only: Alibaba did not release its weights, breaking the open-weight line. Route to Wan 2.1 when you specifically need open weights you can run yourself, or the low per-second cost of the accelerated 480p image-to-video path; for a hosted text-to-video job with no self-hosting requirement, a newer Wan release is usually the better pick.