Gemini 3.1 Pro Preview vs GLM 5.3 FlashX
API pricing, context, and independently measured performance, side by side. GLM 5.3 FlashX starts 82% cheaper on input than Gemini 3.1 Pro Preview at list prices.
Gemini 3.1 Pro Preview
Google · released Feb 19, 2026
Best input$2.00 / MTok
Best output$12.00 / MTok
Context1.05M
Providers6
Fastest measured2.6s° TTFT · 305 tok/s
VisionToolsReasoningStructured outputPrompt caching
GLM 5.3 FlashX
Z.ai · released Sep 18, 2026
Best input$0.37 / MTok
Best output$1.25 / MTok
Context1.05M
Providers1
Fastest measured—
VisionToolsReasoningStructured outputPrompt caching
Cheapest providers, measuredUSD / MTOK
| MODEL | PROVIDER | INPUT | OUTPUT | TTFT | TPS | SMOKE |
|---|---|---|---|---|---|---|
| Gemini 3.1 Pro Preview |  Google | $1.00 | $6.00 | 2.6s° | 305° tok/s | — |
| Gemini 3.1 Pro Preview |  Google AI Studio | $1.00 | $6.00 | 7.4s° | 318° tok/s | — |
| GLM 5.3 FlashX |  Z.AI | $0.37 | $1.25 | — | — | — |
TTFT/TPS: ModelIndex-measured medians (P50, trailing 21d) · chat10k profile (~10K in / 200 out) · ° = measured via OpenRouter routing (adds a hop) · SMOKE: of 5 programmatic capability probes passed · methodology v1.1 — full details on each model page