Google: Gemini 3.1 Pro Preview Custom Tools vs Z.ai: GLM 5.1: Live Promos, Pricing, Hidden Fees & Latency
Verified 2026 FinOps benchmark comparing Google: Gemini 3.1 Pro Preview Custom Tools (google/gemini-3.1-pro-preview-customtools) vs Z.ai: GLM 5.1 (z-ai/glm-5.1). Simulate cache read multipliers, context cliffs, MAU bills, and P90 latency.
Google: Gemini 3.1 Pro Preview Custom Tools (google/gemini-3.1-pro-preview-customtools) — Google AI Startup Credits ($350K) & 50% 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.
Z.ai: GLM 5.1 (z-ai/glm-5.1) 2026 Q4 Developer Promotion & Volume Credits
Official 2026 Q4 promotion for Z.ai: GLM 5.1: Activate ephemeral prefix caching to slash input costs by 50% (down to $0.483/1M) or route via asynchronous Batch API for 50% off standard token rates.
In Etuki October 2026 FinOps telemetry comparing Google: Gemini 3.1 Pro Preview Custom Tools (API ID: google/gemini-3.1-pro-preview-customtools) vs Z.ai: GLM 5.1 (API ID: z-ai/glm-5.1), Z.ai: GLM 5.1 offers lower standard input pricing at $0.966/1M tokens ($3.036/1M output), while Z.ai: GLM 5.1 leads in cached prefix economics at $0.483/1M tokens (50% discount). Google: Gemini 3.1 Pro Preview Custom Tools achieves a 0ms faster P90 time-to-first-token latency (280ms vs 280ms).
Auto-discovered via live global telemetry registry.
Auto-discovered via live global telemetry registry.
| Specification / FinOps Dimension | Google: Gemini 3.1 Pro Preview Custom Tools | Z.ai: GLM 5.1 | Verified Advantage |
|---|---|---|---|
| Official Vendor API ID | google/gemini-3.1-pro-preview-customtools | z-ai/glm-5.1 | Pinned Snapshot IDs |
| Standard Input / Output (per 1M) | $2 / $12 | $0.966 / $3.036 | Z.ai: GLM 5.1 |
| Cache Read Price (per 1M) | $1/1M (50% Off) | $0.483/1M (50% Off) | Z.ai: GLM 5.1 |
| Context Window / Max Output | 1024K In / 64K Out | 200K In / 125K Out | Z.ai: GLM 5.1 |
| P90 First-Token / Edge Latency | 280ms | 280ms | Google: Gemini 3.1 Pro Preview Custom Tools (-0ms) |
Google: Gemini 3.1 Pro Preview Custom Tools
API ID: google/gemini-3.1-pro-preview-customtools • Live RegistryGemini 3.1 Pro Preview Custom Tools is a variant of Gemini 3.1 Pro that improves tool selection behavior by preventing overuse of a general bash tool when more efficient third-part
GLM-5.1 delivers a major leap in coding capability, with particularly significant gains in handling long-horizon tasks. Unlike previous models built around minute-level interaction
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 Google: Gemini 3.1 Pro Preview Custom Tools to Z.ai: GLM 5.1
GLM-5.1 delivers a major leap in coding capability, with particularly significant gains in handling long-horizon tasks. Unlike previous models built around minute-level interaction Verified P90 latency of 280ms.