Z.ai: GLM 4.5 Air vs Google Gemini 3.8 Flash: Live Promos, Pricing, Hidden Fees & Latency
Verified 2026 FinOps benchmark comparing Z.ai: GLM 4.5 Air (z-ai/glm-4.5-air) vs Google Gemini 3.8 Flash (gemini-3.8-flash). Simulate cache read multipliers, context cliffs, MAU bills, and P90 latency.
Z.ai: GLM 4.5 Air (z-ai/glm-4.5-air) 2026 Q4 Developer Promotion & Volume Credits
Official 2026 Q4 promotion for Z.ai: GLM 4.5 Air: Activate ephemeral prefix caching to slash input costs by 50% (down to $0.065/1M) or route via asynchronous Batch API for 50% off standard token rates.
Google Gemini 3.8 Flash (gemini-3.8-flash) — Google AI Startup Credits ($350K) & 80% Cache Promo
Google DeepMind is currently subsidizing Gemini 4 Argon at 50% off standard rates ($2.00/1M input & $10.00/1M output instead of $4/$20) until November 30, 2026, alongside 95% off Context Caching ($0.10/1M) and up to $350,000 in Google for Startups Cloud/Vertex AI credits.
In Etuki October 2026 FinOps telemetry comparing Z.ai: GLM 4.5 Air (API ID: z-ai/glm-4.5-air) vs Google Gemini 3.8 Flash (API ID: gemini-3.8-flash), Z.ai: GLM 4.5 Air offers lower standard input pricing at $0.13/1M tokens ($0.85/1M output), while Google Gemini 3.8 Flash leads in cached prefix economics at $0.03/1M tokens (80% discount). Google Gemini 3.8 Flash achieves a 145ms faster P90 time-to-first-token latency (135ms vs 280ms).
Auto-discovered via live global telemetry registry.
Enable Prompt Context Caching & Batch API to reduce repeated system prompt input token burn by 50%-97.5%.
| Specification / FinOps Dimension | Z.ai: GLM 4.5 Air | Google Gemini 3.8 Flash | Verified Advantage |
|---|---|---|---|
| Official Vendor API ID | z-ai/glm-4.5-air | gemini-3.8-flash | Pinned Snapshot IDs |
| Standard Input / Output (per 1M) | $0.13 / $0.85 | $0.15 / $0.6 | Z.ai: GLM 4.5 Air |
| Cache Read Price (per 1M) | $0.065/1M (50% Off) | $0.03/1M (80% Off) | Google Gemini 3.8 Flash |
| Context Window / Max Output | 128K In / 96K Out | 1000K In / 64K Out | Z.ai: GLM 4.5 Air |
| P90 First-Token / Edge Latency | 280ms | 135ms | Google Gemini 3.8 Flash (-145ms) |
GLM-4.5-Air is the lightweight variant of our latest flagship model family, also purpose-built for agent-centric applications. Like GLM-4.5, it adopts the Mixture-of-Experts (MoE)
High-frequency multimodal, TTS, and live streaming model optimized for low-latency production workloads.
Real-Time Stack Cost & Hidden-Fee Simulator (MAU / Token / Egress / GMV)
Calibrated with Reddit r/FinOps & r/devops telemetry: Includes Context Caching, Bandwidth Egress, and MoR Tax
⚡Switch from Z.ai: GLM 4.5 Air to Google Gemini 3.8 Flash
High-frequency multimodal, TTS, and live streaming model optimized for low-latency production workloads. Verified P90 latency of 135ms.