Model Details
Seed 2.1 Pro
Quick answer: Seed 2.1 Pro is ByteDance's flagship model in the Seed 2.1 family, released June 2026. It delivers significantly improved general agent capabilities, end-to-end coding delivery, and industry-leading multimodal understanding — achieving top scores on benchmarks including CharXiv-RQ, GDPVal, and TVBench.
At a Glance
Where Seed 2.1 Pro leads
- Top-tier visual understanding: highest scores on CharXiv-RQ and MeasureBench for chart, document, and fine-grained visual reasoning
- Strong agent execution: top results on GDPVal (real-world task economic value) and Agents' Last Exam (ALE)
- Video comprehension: industry-leading results on TVBench and TOMATO for temporal and motion understanding
- End-to-end coding: reliable software architecture design and code delivery on ProgramBench
Where it lags
- Closed proprietary model — no open weights
- Pricing and context window specs not publicly disclosed
Best for: High-value agentic workflows requiring reliable multi-step task execution across tools, complex document and visual understanding, and enterprise-grade coding delivery.
What Seed 2.1 Pro Is
Seed 2.1 Pro is ByteDance's flagship general-purpose agent model, the larger of two models in the Seed 2.1 family (alongside Seed 2.1 Turbo). It was designed specifically for real-world productivity scenarios — not just benchmark optimisation — with training calibrated against live workflows from internal and external users.
The model advances across three core dimensions: general agent capabilities (reliable cross-tool and cross-environment task execution), end-to-end coding delivery (requirement analysis through result validation in enterprise development), and multimodal understanding (complex visual, video, and long-context processing that feeds into agentic execution).
Seed 2.1 Pro is accessible through ByteDance's Volcano Engine API under the model ID doubao-seed-2-1-pro, and through the Doubao and Feishu Spark products.
Specifications
| Field | Value |
|---|---|
| Organization | ByteDance |
| Parameters | Undisclosed |
| Context window | Undisclosed |
| Architecture | Undisclosed (Transformer-based) |
| License | Proprietary |
| Release date | 2026-06-23 |
| Knowledge cutoff | 2025-12 |
| Modality | Multimodal (text, image, video) |
Pricing
Pricing is available via Volcano Engine (Doubao API). Specific per-token rates are not publicly listed — check the Volcano Engine console for current rates.
Related Models
- Compare: Seed 2.1 Turbo · Seed 2.0 Pro · Seed 2.0 Lite
Last updated 2026-07-03.
Seed 2.1 Pro vs Alternatives
| Model | AetherCode | Agent Startup Bench | Agents Last Exam |
|---|---|---|---|
| Seed 2.1 Pro | 65.8% | 68.8% | 41.4% |
| Kimi K3 | — | — | — |
| GPT-5.1 Instant | — | — | 6.8% |
Seed 2.1 Pro's 68.8% Agent Startup Bench is competitive at launch. For ALE: scores around 41% appear typical for mid-2026 frontier models.
Frequently Asked Questions
What is Seed 2.1 Pro?
ByteDance's June 2026 model scoring 65.8% AetherCode, 68.8% Agent Startup Bench. Proprietary — ByteDance's frontier API model.Scores from Benchgen evaluations. Last updated 2026-07-24.
Benchmark Leaderboards
This model isn’t on any benchmark leaderboard yet.