DeepSeek-V4 Pro (0813) vs GPT 5.5 Chat Latest — API Pricing, 150K Cache & Latency Benchmark
Side-by-side unit economics audit comparing DeepSeek-V4 Pro (0813) (deepseek/deepseek-v4-pro: Input $0.66/1M, Output $1.98/1M, Warm Cache Read $0.066/1M) against GPT 5.5 Chat Latest (gpt-5-5-chat-latest: Input $1/1M, Output $4/1M, Warm Cache Read $0.1/1M).
Activate 4-breakpoint prefix caching on DeepSeek-V4 Pro (0813) to cut input token costs from $0.66/1M down to $0.066/1M, or route async workloads via Batch API for 50% off.
Lock static system prompt prefixes on GPT 5.5 Chat Latest to pay $0.1/1M warm cache rates instead of $1/1M uncached input, plus eligible startup cloud credits.
In Etuki FinOps telemetry comparing DeepSeek-V4 Pro (0813) (API ID: deepseek/deepseek-v4-pro) vs GPT 5.5 Chat Latest (API ID: gpt-5-5-chat-latest), DeepSeek-V4 Pro (0813) offers lower standard uncached input pricing at $0.66/1M tokens, while DeepSeek-V4 Pro (0813) leads in 10-turn 150K cache-pinned coding economics at $0.2277 per 10 turns (saving $0.1373 over GPT 5.5 Chat Latest). For latency-sensitive interactive agents, GPT 5.5 Chat Latest delivers 40ms faster P90 time-to-first-token (350ms vs 390ms).
| Specification / FinOps Dimension | DeepSeek-V4 Pro (0813) (deepseek/deepseek-v4-pro) | GPT 5.5 Chat Latest (gpt-5-5-chat-latest) | Verified Advantage |
|---|---|---|---|
| Official Vendor API ID | deepseek/deepseek-v4-pro | gpt-5-5-chat-latest | UMCE 563-Registry Locked |
| 563-Registry & Routing Eligibility | is_known: true | routable: true | is_known: true | routable: true | Both Merkle Verified |
| Standard Uncached Input (/1M tokens) | $0.66 / 1M | $1 / 1M | DeepSeek-V4 Pro (0813) |
| Warm Prefix Cache Read (/1M tokens) | $0.066 / 1M | $0.1 / 1M | DeepSeek-V4 Pro (0813) |
| Standard Output (/1M tokens) | $1.98 / 1M | $4 / 1M | DeepSeek-V4 Pro (0813) |
| Context Window Capacity | 200K Tokens | 200K Tokens | DeepSeek-V4 Pro (0813) |
| 150K Prompt × 10 Turns (Unpinned Cold + 2K Out) | $1.0296 | $1.5800 | DeepSeek-V4 Pro (0813) |
| 150K × 10 Turns Case A (100% Static Pinned) | $0.2277 (saves $0.8019) | $0.3650 (saves $1.2150) | DeepSeek-V4 Pro (0813) (-$0.1373) |
| 150K × 10 Turns Case B (90% Static + 10% Tail) | $0.3079 (saves $0.7217) | $0.4865 (saves $1.0935) | DeepSeek-V4 Pro (0813) |
| P50 / P90 First-Token Latency | 265ms / 390ms (96 tok/s) | 238ms / 350ms (87 tok/s) | GPT 5.5 Chat Latest (-40ms) |
1. Full-Turn Rate-Card Substitution for DeepSeek-V4 Pro (0813): At an uncached input rate of $0.66/1M, output rate of $1.98/1M, and warm cache read rate of $0.066/1M, running 10 consecutive 150,000-token coding agent turns (with 2,000 output tokens/turn) without prefix pinning costs $1.0296. Locking 100% static prefixes (Case A: 1 cold turn + 9 warm cached turns + 20K total output) reduces 10-turn spend to $0.2277 (saving $0.8019); under a 90% static prefix + 10% dynamic tail workload (Case B), 10-turn spend is $0.3079.
2. Full-Turn Rate-Card Substitution for GPT 5.5 Chat Latest & Winner Verdict: On GPT 5.5 Chat Latest ($1/1M input, $4/1M output, $0.1/1M warm cache), 10 unpinned 150K turns cost $1.5800, dropping to $0.3650 in Case A and $0.4865 in Case B. Across every 10-turn 150K coding loop (including output tokens), DeepSeek-V4 Pro (0813) delivers an additional $0.1373 Case-A cost advantage.
Production Workload TCO: 25,000 MAU • 50M Tokens/Mo (50% Cache Hit) • 2,000 GB Egress
💡 Optimal FinOps Verdict: Deploying DeepSeek-V4 Pro (0813) saves $27.68/month ($332/year) at 25,000 MAU & 50M monthly tokens (80% input / 20% output split with 50% prefix cache hit rate).