Tencent headquarters in the southern Chinese city of Shenzhen, in
Tencent headquarters in the southern Chinese city of Shenzhen, in Guangdong province. NOEL CELIS/Getty Images

Tencent released and open-sourced its new flagship AI model, Hy4 preview, on Thursday, expanding the system to 770 billion total parameters — 2.6 times the size of last year's Hy3 preview — with a context window that stretches past 1 million tokens. In an internal blind test, the model narrowly beat two of China's other leading systems, even as its price on the open market jumped several times over.

Tencent had 163 of its own engineers grade Hy4 preview against GLM 5.3 and Kimi K3 across 203 real engineering tasks. Hy4 preview averaged 2.99 out of 4, edging out GLM 5.3's 2.92 and Kimi K3's 2.94, according to Tencent's release announcement.

The margins were tight. Hy4 preview won 46.8% of its head-to-head matchups against GLM 5.3, tied 12.8% and lost the rest, Taiwanese outlet BlockTempo reported after reviewing the breakdown. Against Kimi K3, Hy4 preview won 51.2%, tied 7.9% and lost 40.9% — a spread of roughly six percentage points either way.

Pricing tells a sharper story. Tencent lists Hy4 preview at 6 yuan per million input tokens and 18 yuan per million output tokens on its domestic Tencent Cloud TokenHub, translating to roughly $0.834 and $2.501 per million tokens on OpenRouter. That's about 4.6 times the input price and 4.2 times the output price Tencent charged for Hy3 preview on the same platform, BlockTempo found by comparing the two models' OpenRouter listings.

The model is open-sourced under an Apache 2.0 license, with weights posted to Hugging Face and other repositories alongside an FP8 version built for cheaper deployment. It's also live inside Tencent's WorkBuddy and CodeBuddy coding assistants, both of which will offer free access to Hy4 preview for two weeks; free use of Hy3 preview on those same apps has been extended through Sept. 30.

Tencent, a Hang Seng Index constituent trading in Hong Kong as 00700.HK, did not tie the release to any specific business unit or revenue target. The company said the next models in the Hy4 lineup are expected to roll out in the coming weeks.