Head-to-head comparison
KAT-Coder-Pro V2.5 (Kuaishou) and Solar Pro 4 (Upstage) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.
Snapshot as of 3 September 2026
As of 3 September 2026, Solar Pro 4 holds the stronger ModelCap Index position (#58 vs #61); Solar Pro 4 is 24.7× cheaper per output token ($0.12/1M vs $2.96/1M); and Solar Pro 4 offers the longer context window (524K vs 262K tokens).
Evidence: start rank inherited from the measured predecessor in its own product family, less a fixed succession penalty, until independent measurements replace it · 4 public benchmark observations across 4 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.
Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.
Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.
Solar Pro 4 ranks higher on the ModelCap Index as of 3 September 2026: #58 against #61. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it.
Solar Pro 4 is cheaper on output tokens: $0.12/1M against $2.96/1M. Input tokens are $0.74/1M for KAT-Coder-Pro V2.5 and $0.03/1M for Solar Pro 4. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.
Solar Pro 4 has the larger context window: 524K tokens against 262K.
The two models do not share a coding benchmark board on ModelCap yet, so no head-to-head coding score is published; the ModelCap Index position is the closest overall signal.
KAT-Coder-Pro V2.5: API only. Solar Pro 4: API only. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.
ModelCap currently lists 1 API provider for KAT-Coder-Pro V2.5 and 1 for Solar Pro 4, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.
Every figure comes from the sealed ModelCap dataset published 3 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.