OpenAI GPT-5.5 vs Inception: Mercury 2.5: Live Promos, Pricing, Hidden Fees & Latency
Verified 2026 FinOps benchmark comparing OpenAI GPT-5.5 (gpt-5.5) vs Inception: Mercury 2.5 (inception/mercury-2.5). Simulate cache read multipliers, context cliffs, MAU bills, and P90 latency.
OpenAI GPT-5.5 (gpt-5.5) 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).
Inception: Mercury 2.5 (inception/mercury-2.5) 2026 Q4 Developer Promotion & Volume Credits
Official 2026 Q4 promotion for Inception: Mercury 2.5: Activate ephemeral prefix caching to slash input costs by 50% (down to $0.02/1M) or route via asynchronous Batch API for 50% off standard token rates.
In Etuki October 2026 FinOps telemetry comparing OpenAI GPT-5.5 (API ID: gpt-5.5) vs Inception: Mercury 2.5 (API ID: inception/mercury-2.5), Inception: Mercury 2.5 offers lower standard input pricing at $0.04/1M tokens ($0.15/1M output), while Inception: Mercury 2.5 leads in cached prefix economics at $0.02/1M tokens (50% discount). Inception: Mercury 2.5 achieves a 40ms faster P90 time-to-first-token latency (280ms vs 320ms).
Enable Prompt Context Caching & Batch API to reduce repeated system prompt input token burn by 50%-97.5%.
Auto-discovered via live global telemetry registry.
| Specification / FinOps Dimension | OpenAI GPT-5.5 | Inception: Mercury 2.5 | Verified Advantage |
|---|---|---|---|
| Official Vendor API ID | gpt-5.5 | inception/mercury-2.5 | Pinned Snapshot IDs |
| Standard Input / Output (per 1M) | $5 / $30 | $0.04 / $0.15 | Inception: Mercury 2.5 |
| Cache Read Price (per 1M) | $2.5/1M (50% Off) | $0.02/1M (50% Off) | Inception: Mercury 2.5 |
| Context Window / Max Output | 1000K In / 128K Out | 254K In / 64K Out | OpenAI GPT-5.5 |
| P90 First-Token / Edge Latency | 320ms | 280ms | Inception: Mercury 2.5 (-40ms) |
Flagship GPT-5 series general model with configurable reasoning_effort from none to xhigh.
Mercury 2.5 is the fastest reasoning LLM, and the latest diffusion LLM (dLLM) from Inception. Instead of generating tokens sequentially, Mercury 2.5 produces and refines multiple t
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-5.5 to Inception: Mercury 2.5
Mercury 2.5 is the fastest reasoning LLM, and the latest diffusion LLM (dLLM) from Inception. Instead of generating tokens sequentially, Mercury 2.5 produces and refines multiple t Verified P90 latency of 280ms.