Step 3.7 Flash Open vs 
Seed 2.1 Turbo Paid
Step 3.7 Flash vs Seed 2.1 Turbo compared — price per token, context window, multimodality, openness and which to choose. Can the open-source model replace the paid one? Full 2026 breakdown.
Seed 2.1 Turbo — full profile ›
Prices & specs refreshed from live data · olud.ai
Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.
$1.15 /M outputNo per-token fees if you self-host
$2.5 /M outputManaged API (no infra to run)
Step 3.7 Flash vs Seed 2.1 Turbo specs
| Spec | Step 3.7 Flash | Seed 2.1 Turbo | Winner |
|---|---|---|---|
| Maker | Stepfun | ByteDance Seed | – |
| Type | Open-weight | Proprietary | |
| Context window | 262K tokens | 262K tokens | = Tie |
| Input price | $0.2/M · free self-host | $0.5/M | |
| Output price | $1.15/M · free self-host | $2.5/M | |
| Vision / multimodal | Yes | Yes | = Tie |
| Tool / function calling | Yes | Yes | = Tie |
| Self-hostable | Yes | No (API only) | |
| License | Open weights | Proprietary |
Price gap & when to choose each
Step 3.7 Flash is ~2.2× cheaper than Seed 2.1 Turbo on output tokens ($1.15 vs $2.5 per M tokens).
- You want to self-host or run on your cloud
- You prioritize data privacy & control
- You want the lowest operating costs
- You are building open or reproducible AI
- You want frontier performance through a managed API
- You value reliability & ecosystem
- You don't want to manage infrastructure
Feature comparison
| Capability | Step 3.7 Flash | Seed 2.1 Turbo |
|---|---|---|
| Open weights (downloadable) | ✓ | ✗ |
| Self-hostable | ✓ | ✗ |
| Runs fully offline | ✓ | ✗ |
| Vision / multimodal | ✓ | ✓ |
| Tool / function calling | ✓ | ✓ |
| 1M+ context window | ✗ | ✗ |
Benchmarks: Step 3.7 Flash vs Seed 2.1 Turbo
Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).
Benchmark data by Artificial Analysis.
How Step 3.7 Flash and Seed 2.1 Turbo score
| Criterion | Step 3.7 Flash | Seed 2.1 Turbo |
|---|---|---|
| Cost-efficiency | 4.5 | 4.5 |
| Context window | 4.0 | 4.0 |
| Openness | 5.0 | 1.5 |
| Self-hosting | 5.0 | 1.0 |
| Multimodality | 5.0 | 5.0 |
Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.
What each model is
Step 3.7 Flash Open
Step 3.7 Flash is StepFun's latest high-efficiency multimodal Mixture-of-Experts model. It pairs a 196B-parameter language backbone with a vision encoder for native image and video understanding, activating roughly 11B parameters...
Seed 2.1 Turbo Paid
Seed 2.1 Turbo is a multimodal model from ByteDance Seed for coding and long-horizon agent workflows. It is suited for end-to-end software delivery, multi-step task execution, and understanding visual and...
Other models in these families
These variants are tracked but not compared here — one page per family keeps the comparison readable.
Frequently asked questions
Is Step 3.7 Flash as good as Seed 2.1 Turbo?
Step 3.7 Flash is open-weight and competitive on many tasks, but Seed 2.1 Turbo may still lead on the hardest reasoning and agentic work. The gap keeps narrowing — benchmark both on your actual use case before deciding.
Can I run Step 3.7 Flash locally?
Yes. Step 3.7 Flash has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. Seed 2.1 Turbo is API-only and cannot be self-hosted.
How much cheaper is Step 3.7 Flash?
Step 3.7 Flash costs $1.15/M output vs $2.5/M for Seed 2.1 Turbo — roughly 2x cheaper via API, and free if you self-host.
Step 3.7 Flash vs Seed 2.1 Turbo — which should I pick in 2026?
Choose Step 3.7 Flash if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose Seed 2.1 Turbo if you want frontier capability through a managed API with zero infrastructure to run.
People also compare
Explore more open-source AI
Browse the full open-source model leaderboard, thousands of tools and live benchmarks — all in one place.
Open the leaderboard →