Stepfun
Listed at https://platform.stepfun.com
💰 Token Pricing
| Type | Price | Note |
|---|---|---|
| Input | Step-2: ¥6/M, Step-2-mini: ¥1/M, Step-1: ¥4/M, Step-R: ¥8/M | per million tokens |
| Output | Step-2: ¥18/M, Step-2-mini: ¥3/M, Step-1: ¥12/M, Step-R: ¥24/M | per million tokens |
🤖 Supported Models (10)
✨ Pros
- ✓Step-2 trillion-parameter multimodal flagship: text+image+audio+video on a single endpoint
- ✓Direct China access with no proxy, typical TTFT 200-400ms
- ✓OpenAI-compatible /v1/chat/completions endpoint — one-line base_url migration
- ✓Step-R reasoning model at 1/5 the price of OpenAI o1 / DeepSeek R1
- ✓Step-CC code completion with IDE-friendly completions API
⚠️ Cons
- ×Step-2 context window is 128K, behind Kimi K3 (1M) and Qwen3.8-Max (1M)
- ×International endpoint limited to Hong Kong, higher latency from US/EU
- ×No first-class Function Calling support — must simulate via prompts
- ×Model release cadence is moderate, GA timeline for new models is long
- ×No special discounts beyond volume credits
🎯 Best For
Domestic multimodal production workloads; agents that need single-endpoint image/video understanding; cost-sensitive Step-R reasoning as 1/5-price o1 alternative
💰 Pricing & Plans
| Model | Input (¥/M tokens) | Output (¥/M tokens) | Notes |
|---|---|---|---|
| Step-2 | ¥6 (≈$0.83) | ¥18 (≈$2.50) | Trillion-param multimodal flagship, 128K context |
| Step-2-mini | ¥1 (≈$0.14) | ¥3 (≈$0.42) | Fast Step-2 variant, 32K context, 200B params |
| Step-1 | ¥4 (≈$0.56) | ¥12 (≈$1.67) | 300B multimodal, 32K context, prior gen |
| Step-1V / Step-1.5V | ¥3 (≈$0.42) | ¥9 (≈$1.25) | Vision-tuned, 100B-200B |
| Step-R | ¥8 (≈$1.11) | ¥24 (≈$3.33) | Reasoning (o1 / DeepSeek R1 class) |
| Step-CC | ¥1 (≈$0.14) | ¥2 (≈$0.28) | Code completion, IDE-friendly |
🔧 API & Developer Experience
- •API Style: OpenAI-compatible /v1/chat/completions endpoint — drop-in replacement by changing base_url.
- •Base URL: https://platform.stepfun.com/v1 — direct from mainland China, no proxy required.
- •SDK Compatibility: Works with the official OpenAI Python/Node SDKs by swapping base_url and api_key. Stepfun also ships a first-party Python SDK with multimodal helpers at github.com/stepfun-ai.
- •Multimodal Inputs: Step-2 and Step-2-mini accept image_url, video_url and audio_url content parts in the same chat-completions request — no separate vision API.
- •Streaming: Server-Sent Events (SSE) streaming for both text and multimodal responses; token usage is reported in the final chunk.
- •Function Calling: Beta: tools parameter accepted, but structured tool_choice is incomplete. Production callers usually wrap Step-2 in a prompt-engineering layer for tool routing.
- •Rate Limits: Default 60 RPM / 100,000 TPM on free tier, raises to 600 RPM / 10M TPM after first top-up. Concurrency 5/20/100 across tier ladder.
🧠 Step-2 万亿参数多模态能力
Step-2 is Stepfun's 1.2T-parameter multimodal flagship, accepting text, image, audio and video inputs through a single /v1/chat/completions surface. Where competing China LLMs (DeepSeek V3.2, Qwen3.5-Max, Moonshot Kimi K3) require separate vision endpoints or per-modality pricing, Step-2 treats every input as a content part, so a video understanding call is billed the same way as a text chat. The 128K context window is mid-pack — behind Kimi K3 (1M) and Qwen3.8-Max (1M), but ahead of DeepSeek V3.2 (64K default, 128K max). For multimodal benchmarks Step-2 lands inside the top-3 of the China open-weight cohort on MMMU, MMBench and MathVista, and the Step-1.5V vision model ranked top-1 on the Chinese-language CV-Bench-QA in early 2026. In production the model is a strong fit for short-clip video understanding (≤2 minutes), OCR-heavy document reasoning, and long-form image+text RAG — the context window and structured output stability are its biggest advantages over DeepSeek V3.2's text-first pipeline.
🌐 Regional Availability & Latency
Stepfun is the second major China LLM provider (after DeepSeek) with first-party direct access from mainland China. The platform.stepfun.com endpoint serves China-based traffic over domestic BGP routes, with typical TTFT of 200-400ms and generation throughput of 40-80 tokens/sec for Step-2. International traffic is served via the Hong Kong PoP, where US/EU callers see 150-300ms TTFT. There is no published Singapore or Tokyo edge as of August 2026 — agents serving East Asia outside China should benchmark before deploying. For production workloads in mainland China, Stepfun is one of three credible first-party endpoints (alongside DeepSeek and SiliconFlow) that bypass the OpenAI / Anthropic proxy requirement entirely. Cross-region routing is the standard production pattern for agents that need both domestic China and overseas users — Stepfun for the China leg, OpenRouter or the upstream provider directly for the international leg. The OpenAI-compatible surface makes this split trivial: only the base_url changes per request.