OpenAI: GPT-5.1-Codex vs Google: Gemini 3.1 Pro Preview Custom Tools: Live Promos, Pricing, Hidden Fees & Latency
Verified 2026 FinOps benchmark comparing OpenAI: GPT-5.1-Codex (openai/gpt-5.1-codex) vs Google: Gemini 3.1 Pro Preview Custom Tools (google/gemini-3.1-pro-preview-customtools). Simulate cache read multipliers, context cliffs, MAU bills, and P90 latency.
OpenAI: GPT-5.1-Codex (openai/gpt-5.1-codex) 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).
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.
In Etuki October 2026 FinOps telemetry comparing OpenAI: GPT-5.1-Codex (API ID: openai/gpt-5.1-codex) vs Google: Gemini 3.1 Pro Preview Custom Tools (API ID: google/gemini-3.1-pro-preview-customtools), OpenAI: GPT-5.1-Codex offers lower standard input pricing at $1.25/1M tokens ($10/1M output), while OpenAI: GPT-5.1-Codex leads in cached prefix economics at $0.625/1M tokens (50% discount). OpenAI: GPT-5.1-Codex 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-5.1-Codex | Google: Gemini 3.1 Pro Preview Custom Tools | Verified Advantage |
|---|---|---|---|
| Official Vendor API ID | openai/gpt-5.1-codex | google/gemini-3.1-pro-preview-customtools | Pinned Snapshot IDs |
| Standard Input / Output (per 1M) | $1.25 / $10 | $2 / $12 | OpenAI: GPT-5.1-Codex |
| Cache Read Price (per 1M) | $0.625/1M (50% Off) | $1/1M (50% Off) | OpenAI: GPT-5.1-Codex |
| Context Window / Max Output | 391K In / 125K Out | 1024K In / 64K Out | OpenAI: GPT-5.1-Codex |
| P90 First-Token / Edge Latency | 280ms | 280ms | OpenAI: GPT-5.1-Codex (-0ms) |
GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows. It is designed for both interactive development sessions and long, indepe
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
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-5.1-Codex to Google: Gemini 3.1 Pro Preview Custom Tools
Gemini 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 Verified P90 latency of 280ms.