Step 3.7 Flash vs Solar Pro 4
Step 3.7 Flash comes out ahead, 63 to 53 on our weighted score, and it is the cheaper option too.
- Our pick
StepFunStep 3.7 Flash
63/100- ECI—
- Price$0.20 / $1.15
- Context256K
UpstageSolar Pro 4
53/100- ECI—
- Price$0.30 / $1.20
- Context524K
Add a model
Make it a three-way comparison.
Step 3.7 Flash is our pick
Step 3.7 Flash is the better all-round choice, scoring 63/100 against Solar Pro 4 (53). It leads on price and inputs & features. Solar Pro 4 wins on context window. 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 3.7 FlashStep 3.7 Flash $0.438 · Solar Pro 4 $0.525 per 1M tokens (3:1 blend)
- Longest contextSolar Pro 4Solar Pro 4 524,288 · Step 3.7 Flash 256,000 tokens
- Widest inputsStep 3.7 FlashStep 3.7 Flash: Text, Images, Video · Solar Pro 4: Text
- Self-hostingStep 3.7 FlashPublishes downloadable weights
| Measure | Weight | Step 3.7 Flash | Solar Pro 4 |
|---|---|---|---|
| Price | 50% | 64 | 60 |
| Inputs & features | 30% | 80 | 45 |
| Context window | 20% | 36 | 49 |
| Overall | 100% | 63/100 | 53/100 |
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 3.7 FlashStepFun | Solar Pro 4Upstage |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | — |
| ECI rank | — | — |
| Price per million tokens | ||
| Input | $0.20 (best) | $0.30 |
| Output | $1.15 (best) | $1.20 |
| Cached input | $0.04 (best) | $0.06 |
| Blended (3:1) | $0.438 (best) | $0.525 |
| Long-context rate | Same rate | Same rate |
| Price source | Official StepFun (Global) API | Official Upstage API |
| Limits | ||
| Context window | 256,000 tokens | 524,288 tokens (best) |
| Max output | 256,000 tokens (best) | 131,072 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | No |
| PDFs | No | No |
| Audio | No | No |
| Video | Yes | No |
| Reasoning | Yeslow · medium · high | Yesminimal · low · medium · high · xhigh · max |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Open | Proprietary |
| API model ID | step-3.7-flash | solar-pro4 |
| API providers | 19 (best) | 6 |
| Released | May 29, 2026 | Aug 6, 2026 |
| Knowledge cutoff | Mar 1, 2026 | Feb 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Step 3.7 Flash$4.30
- Solar Pro 4$5.40
Which should you choose?
Which is better: Step 3.7 Flash or Solar Pro 4?
Step 3.7 Flash is the better all-round choice, scoring 63/100 against Solar Pro 4 (53). It leads on price and inputs & features. Solar Pro 4 wins on context window. 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 3.7 Flash or Solar Pro 4?
Step 3.7 Flash is cheaper at $0.20 input / $1.15 output per million tokens (official StepFun (Global) API price). Solar Pro 4 costs $0.30 input / $1.20 output per million tokens (official Upstage API price). At a typical mix of three input tokens to one output token, that is $0.438 per million tokens for Step 3.7 Flash versus $0.525 for Solar Pro 4 (1.2× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. Step 3.7 Flash has not been scored yet and Solar Pro 4 has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Step 3.7 Flash and Solar Pro 4 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?
Solar Pro 4 has the largest context window at 524,288 tokens, against 256,000 for Step 3.7 Flash. Maximum output per response: Step 3.7 Flash up to 256,000, Solar Pro 4 up to 131,072 tokens.
Which can read images, PDFs, audio or video?
Step 3.7 Flash accepts text, images and video; Solar Pro 4 accepts text. Step 3.7 Flash handles the widest range of inputs.
Are any of these open source?
Step 3.7 Flash publishes its weights and can be self-hosted; Solar Pro 4 is proprietary.
Which is newer?
Solar Pro 4 is the newest, released Aug 6, 2026. Step 3.7 Flash came out May 29, 2026. Knowledge cutoff: Step 3.7 Flash Mar 1, 2026, Solar Pro 4 Feb 2026.
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 Nov 2, 2026.
