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ByteDanceTextUncommon

Seed 2.1 Pro

Flagship ByteDance Seed 2.1 model for complex multimodal reasoning, coding, and agents

doubao-seed-2-1-pro-260628
Type
Text
Quality
64 · Top 36% on the LMArena WebDev
Context window
256,000 tokens
Max output
256,000 tokens
Input price
$0.89 / 1M tokens
Output price
$4.45 / 1M tokens
Cache read
$0.18 / 1M tokens
Cache write
—
Released
Jun 23, 2026
Knowledge cutoff
—
Takes in
Text, Image, Video
Puts out
Text
Reasoning
Yes
Tool calling
Yes
Structured output
Yes
File attachments
Yes
Access
Paid
License
Proprietary
Rarity
Uncommon
Set number
929/1044
Open ByteDance docsQuality 64Where to run it 2Evolution 2/2Meet its creatureBattle GPT-5.4 mini

Weights aren’t public. Use is governed by ByteDance’s terms. Specs from models.dev, last changed Oct 19, 2026. Official source: www.volcengine.com.

How good is it?

Public leaderboard scores for Seed 2.1 Pro, refreshed daily from Epoch AI and LMArena.

Top 36% of the 145 models on the LMArena WebDev: #53.

Quality is the share of a leaderboard’s models this one beats, from 0 to 100. Chat models are rated on Epoch AI’s Capabilities Index when it lists them, otherwise on LMArena; image and video models on LMArena’s image and video arenas.

Leaderboards

Scores from LMArena, licensed CC BY 4.0. Boards list models under their own names, so a close match is shown with the name it was scored under. Credits

Where to run it

2 providers sell Seed 2.1 Pro through an API. Prices are per million tokens, cheapest first.

API providers

ProviderInputOutputContext
OfoxCheapest paidvolcengine/doubao-seed-2.1-pro$0.71$3.54256K
Volcengine ArkOfficialdoubao-seed-2-1-pro-260628$0.89$4.45256K

From models.dev and Hugging Face, checked daily. Resellers’ listings can lag behind their price pages, so confirm with the provider before you commit.

Face off

Current text models from other labs at a similar output price.

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