StepFun: Step 3.5 Flash vs Anthropic Claude Opus 5.5: Live Promos, Pricing, Hidden Fees & Latency
Verified 2026 FinOps benchmark comparing StepFun: Step 3.5 Flash (stepfun/step-3.5-flash) vs Anthropic Claude Opus 5.5 (claude-opus-5-5). Simulate cache read multipliers, context cliffs, MAU bills, and P90 latency.
StepFun: Step 3.5 Flash (stepfun/step-3.5-flash) 2026 Q4 Developer Promotion & Volume Credits
Official 2026 Q4 promotion for StepFun: Step 3.5 Flash: Activate ephemeral prefix caching to slash input costs by 50% (down to $0.05/1M) or route via asynchronous Batch API for 50% off standard token rates.
Claude for Startups Program ($25,000 API Credits) & 95% Off Ephemeral Cache Reads
Anthropic's Q4 2026 developer promotion combines $25,000 in Claude API credits for early-stage builders with a permanent 20% base price reduction on Opus 5.5 ($4/$20), 0.05x ($0.20/1M) prompt cache reads, and 50% off Batch API processing ($2/$10 with 300K max output).
In Etuki October 2026 FinOps telemetry comparing StepFun: Step 3.5 Flash (API ID: stepfun/step-3.5-flash) vs Anthropic Claude Opus 5.5 (API ID: claude-opus-5-5), StepFun: Step 3.5 Flash offers lower standard input pricing at $0.1/1M tokens ($0.3/1M output), while StepFun: Step 3.5 Flash leads in cached prefix economics at $0.05/1M tokens (50% discount). StepFun: Step 3.5 Flash achieves a 70ms faster P90 time-to-first-token latency (280ms vs 350ms).
Auto-discovered via live global telemetry registry.
Adaptive thinking is always on; high effort generates ~119K thinking tokens/task. Fast mode costs $8/$40; inference_geo:"us" adds +10%.
| Specification / FinOps Dimension | StepFun: Step 3.5 Flash | Anthropic Claude Opus 5.5 | Verified Advantage |
|---|---|---|---|
| Official Vendor API ID | stepfun/step-3.5-flash | claude-opus-5-5 | Pinned Snapshot IDs |
| Standard Input / Output (per 1M) | $0.1 / $0.3 | $4 / $20 | StepFun: Step 3.5 Flash |
| Cache Read Price (per 1M) | $0.05/1M (50% Off) | $0.2/1M (95% Off) | StepFun: Step 3.5 Flash |
| Context Window / Max Output | 256K In / 64K Out | 1000K In / 128K Out | Anthropic Claude Opus 5.5 |
| P90 First-Token / Edge Latency | 280ms | 350ms | StepFun: Step 3.5 Flash (-70ms) |
Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parame
Ranked #1 on Artificial Analysis Intelligence Index (Score 58). Cuts Opus 5 pricing by 20% and features 0.05x ($0.20/1M) cache reads.
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 StepFun: Step 3.5 Flash to Anthropic Claude Opus 5.5
Ranked #1 on Artificial Analysis Intelligence Index (Score 58). Cuts Opus 5 pricing by 20% and features 0.05x ($0.20/1M) cache reads. Verified P90 latency of 350ms.