OpenAI GPT-5.6 Terra vs Anthropic Claude Sonnet 5.5: Live Promos, Pricing, Hidden Fees & Latency
Verified 2026 FinOps benchmark comparing OpenAI GPT-5.6 Terra (gpt-5.6-terra) vs Anthropic Claude Sonnet 5.5 (claude-sonnet-5-5). Simulate cache read multipliers, context cliffs, MAU bills, and P90 latency.
OpenAI GPT-5.6 Terra (gpt-5.6-terra) 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).
Sonnet 5.5 High-Velocity Coding Promo: $0.10/1M Cached Input & $1/$5 Batch Tier
Anthropic's September/October 2026 rollout prices Claude Sonnet 5.5 at half of Opus 5.5 ($2/$10) while activating $0.10/1M (0.05x) cached input reads and $1.00/$5.00 asynchronous batch processing.
In Etuki October 2026 FinOps telemetry comparing OpenAI GPT-5.6 Terra (API ID: gpt-5.6-terra) vs Anthropic Claude Sonnet 5.5 (API ID: claude-sonnet-5-5), OpenAI GPT-5.6 Terra offers lower standard input pricing at $2/1M tokens ($12/1M output), while Anthropic Claude Sonnet 5.5 leads in cached prefix economics at $0.1/1M tokens (95% discount). Anthropic Claude Sonnet 5.5 achieves a 60ms faster P90 time-to-first-token latency (230ms vs 290ms).
Enable Prompt Context Caching & Batch API to reduce repeated system prompt input token burn by 50%-97.5%.
Enable Prompt Context Caching & Batch API to reduce repeated system prompt input token burn by 50%-97.5%.
| Specification / FinOps Dimension | OpenAI GPT-5.6 Terra | Anthropic Claude Sonnet 5.5 | Verified Advantage |
|---|---|---|---|
| Official Vendor API ID | gpt-5.6-terra | claude-sonnet-5-5 | Pinned Snapshot IDs |
| Standard Input / Output (per 1M) | $2 / $12 | $2 / $10 | OpenAI GPT-5.6 Terra |
| Cache Read Price (per 1M) | $1/1M (50% Off) | $0.1/1M (95% Off) | Anthropic Claude Sonnet 5.5 |
| Context Window / Max Output | 400K In / 128K Out | 1000K In / 128K Out | OpenAI GPT-5.6 Terra |
| P90 First-Token / Edge Latency | 290ms | 230ms | Anthropic Claude Sonnet 5.5 (-60ms) |
Balanced enterprise general-purpose model in the GPT-5.6 family with 1M context window.
Released Sept 28, 2026 at half of Opus 5.5 price with 0.05x ($0.10/1M) cache reads for high-speed SWE agents.
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-5.6 Terra to Anthropic Claude Sonnet 5.5
Released Sept 28, 2026 at half of Opus 5.5 price with 0.05x ($0.10/1M) cache reads for high-speed SWE agents. Verified P90 latency of 230ms.