OpenAI: GPT-5.4 Image 2 vs Z.ai: GLM 5.1: Live Promos, Pricing, Hidden Fees & Latency
Verified 2026 FinOps benchmark comparing OpenAI: GPT-5.4 Image 2 (openai/gpt-5.4-image-2) vs Z.ai: GLM 5.1 (z-ai/glm-5.1). Simulate cache read multipliers, context cliffs, MAU bills, and P90 latency.
OpenAI: GPT-5.4 Image 2 (openai/gpt-5.4-image-2) Startup Credits & Batch API 50% Off Promo
OpenAI GPT-6.1 Sol ($2/$10 base rate) qualifies for immediate 75% automatic prefix caching ($0.50/1M), 50% off 24-hour Batch API completions ($1/$5), and up to $150,000 in OpenAI/Azure Foundry credits via Microsoft for Startups Founders Hub (no VC funding required for initial tiers).
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 OpenAI: GPT-5.4 Image 2 (API ID: openai/gpt-5.4-image-2) 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). OpenAI: GPT-5.4 Image 2 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 | OpenAI: GPT-5.4 Image 2 | Z.ai: GLM 5.1 | Verified Advantage |
|---|---|---|---|
| Official Vendor API ID | openai/gpt-5.4-image-2 | z-ai/glm-5.1 | Pinned Snapshot IDs |
| Standard Input / Output (per 1M) | $8 / $15 | $0.966 / $3.036 | Z.ai: GLM 5.1 |
| Cache Read Price (per 1M) | $4/1M (50% Off) | $0.483/1M (50% Off) | Z.ai: GLM 5.1 |
| Context Window / Max Output | 266K In / 125K Out | 200K In / 125K Out | OpenAI: GPT-5.4 Image 2 |
| P90 First-Token / Edge Latency | 280ms | 280ms | OpenAI: GPT-5.4 Image 2 (-0ms) |
[GPT-5.4](https://openrouter.ai/openai/gpt-5.4) Image 2 combines OpenAI's GPT-5.4 model with state-of-the-art image generation capabilities from GPT Image 2. It enables rich multim
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 OpenAI: GPT-5.4 Image 2 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.