GPT-6 Astra vs GLM 5.3 FlashX
API pricing, context, and independently measured performance, side by side. GLM 5.3 FlashX starts 96% cheaper on input than GPT-6 Astra at list prices.
GPT-6 Astra
OpenAI · released Sep 4, 2026
Best input$10.00 / MTok
Best output$50.00 / MTok
Context1.05M
Providers5
Fastest measured4.2s° TTFT · 116 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 |
|---|---|---|---|---|---|---|
| GPT-6 Astra |  OpenAI | $5.00 | $25.00 | 4.2s° | 116° tok/s | — |
| GPT-6 Astra |  Azure | $10.00 | $50.00 | 4.3s° | 187° 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