Hy4 preview vs Kimi K2.8 Preview vs Step 5 Preview
Step 5 Preview comes out ahead, 56 to 51 and 44 on our weighted score, though Hy4 preview is 12% cheaper per token.
TencentHy4 preview
44/100- ECI—
- Price$0.834 / $2.50
- Context1.02M
Moonshot AIKimi K2.8 Preview
51/100- ECI—
- Price$1.00 / $4.00
- Context1.05M
- Our pick
StepFunStep 5 Preview
56/100- ECI—
- Price$1.00 / $2.70
- Context1M
Step 5 Preview is our pick
Step 5 Preview is the better all-round choice, scoring 56/100 against Kimi K2.8 Preview (51) and Hy4 preview (44). It leads on inputs & features. Hy4 preview 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 priceHy4 previewHy4 preview $1.25 · Step 5 Preview $1.43 · Kimi K2.8 Preview $1.75 per 1M tokens (3:1 blend)
- Longest contextKimi K2.8 PreviewKimi K2.8 Preview 1,048,576 · Hy4 preview 1,024,000 · Step 5 Preview 1,000,000 tokens
- Widest inputsKimi K2.8 Preview and Step 5 PreviewHy4 preview: Text · Kimi K2.8 Preview: Text, Images, Video · Step 5 Preview: Text, Images, Video
- Self-hostingHy4 preview and Step 5 PreviewPublishes downloadable weights
| Measure | Weight | Hy4 preview | Kimi K2.8 Preview | Step 5 Preview |
|---|---|---|---|---|
| Price | 50% | 43 | 37 | 41 |
| Inputs & features | 30% | 35 | 70 | 80 |
| Context window | 20% | 60 | 61 | 60 |
| Overall | 100% | 44/100 | 51/100 | 56/100 |
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 | Hy4 previewTencent | Kimi K2.8 PreviewMoonshot AI | Step 5 PreviewStepFun |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | — | — | — |
| ECI rank | — | — | — |
| Price per million tokens | |||
| Input | $0.834 (best) | $1.00 | $1.00 |
| Output | $2.50 (best) | $4.00 | $2.70 |
| Cached input | $0.042 (best) | — | $0.10 |
| Blended (3:1) | $1.25 (best) | $1.75 | $1.43 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Tencent TokenHub API | Median of 2 providers | Official StepFun (Global) API |
| Limits | |||
| Context window | 1,024,000 tokens | 1,048,576 tokens (best) | 1,000,000 tokens |
| Max output | 64,000 tokens | — | 1,000,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | No | Yes | Yes |
| PDFs | No | No | No |
| Audio | No | No | No |
| Video | No | Yes | Yes |
| Reasoning | Yeshigh | Yes | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | No | No | Yes |
| Availability | |||
| Weights | Open | Proprietary | Open |
| API model ID | hy4-preview | — | step-5-preview |
| API providers | 17 | 2 | 18 (best) |
| Released | Aug 28, 2026 | Sep 11, 2026 | Sep 16, 2026 |
| Knowledge cutoff | — | — | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Hy4 preview$13.34
- Kimi K2.8 Preview$18.00
- Step 5 Preview$15.40
Which should you choose?
Which is better: Hy4 preview, Kimi K2.8 Preview or Step 5 Preview?
Step 5 Preview is the better all-round choice, scoring 56/100 against Kimi K2.8 Preview (51) and Hy4 preview (44). It leads on inputs & features. Hy4 preview 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, Hy4 preview, Kimi K2.8 Preview or Step 5 Preview?
Hy4 preview is cheaper at $0.834 input / $2.50 output per million tokens (official Tencent TokenHub API price). Step 5 Preview costs $1.00 input / $2.70 output per million tokens (official StepFun (Global) API price); Kimi K2.8 Preview costs $1.00 input / $4.00 output per million tokens (median across 2 API providers). At a typical mix of three input tokens to one output token, that is $1.25 per million tokens for Hy4 preview versus $1.43 for Step 5 Preview (1.1× as much) and $1.75 for Kimi K2.8 Preview (1.4× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. Hy4 preview has not been scored yet, Kimi K2.8 Preview has not been scored yet and Step 5 Preview has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for Hy4 preview, Kimi K2.8 Preview and Step 5 Preview yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. All three support tool calling for agent workflows.
Which has the bigger context window?
Kimi K2.8 Preview has the largest context window at 1,048,576 tokens, against 1,024,000 for Hy4 preview and 1,000,000 for Step 5 Preview. Maximum output per response: Hy4 preview up to 64,000, Step 5 Preview up to 1,000,000 tokens.
Which can read images, PDFs, audio or video?
Hy4 preview accepts text; Kimi K2.8 Preview accepts text, images and video; Step 5 Preview accepts text, images and video. Kimi K2.8 Preview handles the widest range of inputs.
Are any of these open source?
Hy4 preview and Step 5 Preview publishes its weights and can be self-hosted; Kimi K2.8 Preview is proprietary.
Which is newer?
Step 5 Preview is the newest, released Sep 16, 2026. Kimi K2.8 Preview came out Sep 11, 2026; Hy4 preview came out Aug 28, 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.
