Step 3.5 Flash vs Seed 2.0 Lite
Seed 2.0 Lite comes out ahead, 73 to 62 on our weighted score, though Step 3.5 Flash is 25% cheaper per token.
StepFunStep 3.5 Flash
62/100- ECI—
- Price$0.10 / $0.30
- Context256K
- Our pick
ByteDance SeedSeed 2.0 Lite
73/100- ECI—
- Price$0.089 / $0.534
- Context256K
Add a model
Make it a three-way comparison.
Seed 2.0 Lite is our pick
Seed 2.0 Lite is the better all-round choice, scoring 73/100 against Step 3.5 Flash (62). It leads on inputs & features. Step 3.5 Flash wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceStep 3.5 FlashStep 3.5 Flash $0.15 · Seed 2.0 Lite $0.20 per 1M tokens (3:1 blend)
- Longest contextAbout the sameStep 3.5 Flash 256,000 · Seed 2.0 Lite 256,000 tokens
- Widest inputsSeed 2.0 LiteStep 3.5 Flash: Text · Seed 2.0 Lite: Text, Images, Video
- Self-hostingStep 3.5 FlashPublishes downloadable weights
| Measure | Weight | Step 3.5 Flash | Seed 2.0 Lite |
|---|---|---|---|
| Price | 50% | 89 | 83 |
| Inputs & features | 30% | 35 | 80 |
| Context window | 20% | 36 | 36 |
| Overall | 100% | 62/100 | 73/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Step 3.5 FlashStepFun | Seed 2.0 LiteByteDance Seed |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $0.10 | $0.089 (best) |
| Output | $0.30 (best) | $0.534 |
| Cached input | $0.02 | $0.018 (best) |
| Blended (3:1) | $0.15 (best) | $0.20 |
| Long-context rate | Same rate | Over 32K: $0.134 / $0.802 |
| Price source | Official StepFun (Global) API | Official Volcengine Ark API |
| Limits | ||
| Context window | 256,000 tokens | 256,000 tokens |
| Max output | 256,000 tokens (best) | 32,000 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | No | Yes |
| PDFs | No | No |
| Audio | No | No |
| Video | No | Yes |
| Reasoning | Yeslow · high | Yesminimal · low · medium · high · xhigh · max |
| Tool calling | Yes | Yes |
| Structured output | No | Yes |
| Availability | ||
| Weights | Open | Proprietary |
| API model ID | step-3.5-flash | doubao-seed-2-0-lite-260428 |
| API providers | 8 (best) | 6 |
| Released | Jan 29, 2026 | Feb 14, 2026 |
| Knowledge cutoff | Jan 2025 | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Step 3.5 Flash$1.60
- Seed 2.0 Lite$1.96
Which should you choose?
Which is better: Step 3.5 Flash or Seed 2.0 Lite?
Seed 2.0 Lite is the better all-round choice, scoring 73/100 against Step 3.5 Flash (62). It leads on inputs & features. Step 3.5 Flash wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, Step 3.5 Flash or Seed 2.0 Lite?
Step 3.5 Flash is cheaper at $0.10 input / $0.30 output per million tokens (official StepFun (Global) API price). Seed 2.0 Lite costs $0.089 input / $0.534 output per million tokens (official Volcengine Ark API price). At a typical mix of three input tokens to one output token, that is $0.15 per million tokens for Step 3.5 Flash versus $0.20 for Seed 2.0 Lite (1.3× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Step 3.5 Flash has not been scored yet and Seed 2.0 Lite has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Step 3.5 Flash and Seed 2.0 Lite yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.
Which has the bigger context window?
Step 3.5 Flash and Seed 2.0 Lite share the same 256,000-token context window. Maximum output per response: Step 3.5 Flash up to 256,000, Seed 2.0 Lite up to 32,000 tokens.
Which can read images, PDFs, audio or video?
Step 3.5 Flash accepts text; Seed 2.0 Lite accepts text, images and video. Seed 2.0 Lite handles the widest range of inputs.
Are any of these open source?
Step 3.5 Flash publishes its weights and can be self-hosted; Seed 2.0 Lite is proprietary.
Which is newer?
Seed 2.0 Lite is the newest, released Feb 14, 2026. Step 3.5 Flash came out Jan 29, 2026. Knowledge cutoff: Step 3.5 Flash Jan 2025.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
