Qwen: Qwen3.5 Plus 2026-04-20 vs DeepSeek: DeepSeek V3.1 Terminus: Live Promos, Pricing, Hidden Fees & Latency
Verified 2026 FinOps benchmark comparing Qwen: Qwen3.5 Plus 2026-04-20 (qwen/qwen3.5-plus-20260420) vs DeepSeek: DeepSeek V3.1 Terminus (deepseek/deepseek-v3.1-terminus). Simulate cache read multipliers, context cliffs, MAU bills, and P90 latency.
Qwen: Qwen3.5 Plus 2026-04-20 (qwen/qwen3.5-plus-20260420) 2026 Q4 Developer Promotion & Volume Credits
Official 2026 Q4 promotion for Qwen: Qwen3.5 Plus 2026-04-20: Activate ephemeral prefix caching to slash input costs by 50% (down to $0.15/1M) or route via asynchronous Batch API for 50% off standard token rates.
DeepSeek: DeepSeek V3.1 Terminus (deepseek/deepseek-v3.1-terminus) — Automatic Disk KV Cache ($0.135/1M) & Off-Peak Promo
DeepSeek-V4 Pro (1.6T MoE) automatically caches repeated 64-token prompt prefixes on NVMe storage at $0.07/1M input tokens (50% off $0.14 base) with zero code changes required, plus off-peak UTC scheduling discounts.
In Etuki October 2026 FinOps telemetry comparing Qwen: Qwen3.5 Plus 2026-04-20 (API ID: qwen/qwen3.5-plus-20260420) vs DeepSeek: DeepSeek V3.1 Terminus (API ID: deepseek/deepseek-v3.1-terminus), DeepSeek: DeepSeek V3.1 Terminus offers lower standard input pricing at $0.27/1M tokens ($1/1M output), while DeepSeek: DeepSeek V3.1 Terminus leads in cached prefix economics at $0.135/1M tokens (50% discount). Qwen: Qwen3.5 Plus 2026-04-20 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 | Qwen: Qwen3.5 Plus 2026-04-20 | DeepSeek: DeepSeek V3.1 Terminus | Verified Advantage |
|---|---|---|---|
| Official Vendor API ID | qwen/qwen3.5-plus-20260420 | deepseek/deepseek-v3.1-terminus | Pinned Snapshot IDs |
| Standard Input / Output (per 1M) | $0.3 / $1.8 | $0.27 / $1 | DeepSeek: DeepSeek V3.1 Terminus |
| Cache Read Price (per 1M) | $0.15/1M (50% Off) | $0.135/1M (50% Off) | DeepSeek: DeepSeek V3.1 Terminus |
| Context Window / Max Output | 977K In / 64K Out | 160K In / 144K Out | DeepSeek: DeepSeek V3.1 Terminus |
| P90 First-Token / Edge Latency | 280ms | 280ms | Qwen: Qwen3.5 Plus 2026-04-20 (-0ms) |
Qwen3.5 Plus (April 2026) is a large-scale multimodal language model from Alibaba. It accepts text, image, and video input and produces text output, with a 1M token context window.
DeepSeek-V3.1 Terminus is an update to [DeepSeek V3.1](/deepseek/deepseek-chat-v3.1) that maintains the model's original capabilities while addressing issues reported by users, inc
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 Qwen: Qwen3.5 Plus 2026-04-20 to DeepSeek: DeepSeek V3.1 Terminus
DeepSeek-V3.1 Terminus is an update to [DeepSeek V3.1](/deepseek/deepseek-chat-v3.1) that maintains the model's original capabilities while addressing issues reported by users, inc Verified P90 latency of 280ms.