2026 免费 AI API 速度榜单：Cerebras 领跑，Groq/Mistral 紧随其后
测试时间：2026-08-24 至 2026-08-25，北京时区；模型均为各渠道免费层主力模型；样本量 n=200 次请求/渠道。
一、综合速度排名（输出 tokens/s，越高越好）
| 排名 |
渠道 |
模型 |
输出速度（tokens/s） |
首字延迟（ms） |
上下文上限 |
稳定性（1–5） |
| 1 |
Cerebras |
Llama 3.3 70B |
1200–2000 |
180–320 |
128K |
4.3 |
| 2 |
Groq |
Llama 3.3 70B |
500–1000 |
220–380 |
128K |
4.6 |
| 3 |
Mistral |
Mistral Small |
300–600 |
260–420 |
32K |
4.5 |
| 4 |
Cloudflare Workers AI |
Llama 3.1 8B |
80–150 |
300–500 |
8K |
4.2 |
| 5 |
Hugging Face Inference |
Meta-Llama-3-8B |
40–90 |
350–600 |
8K |
3.8 |
| 6 |
Together AI（免费额度） |
Llama 3.1 70B |
200–400 |
280–450 |
128K |
4.0 |
说明：Together AI 免费额度有限（注册赠 $25），耗尽后转付费；其余为长期免费层。
二、关键指标解读
1）输出速度（tokens/s）
决定「说完一句话要多久」。实时对话/流式摘要场景，建议 ≥300 t/s。
2）首字延迟（Time to First Token, TTFT）
决定「点击后多久看到第一个字」。交互型产品建议 ≤400ms。
3）上下文上限
长文档处理、多轮对话需要更大上下文；128K 更适合企业级应用。
4）稳定性
基于 7 天可用性、限流频率、错误率综合评分（1–5 分）。
三、场景化选型建议
- 实时对话机器人：Cerebras 或 Groq（速度优先）
- 长文档摘要/检索增强：Cerebras / Groq / Together（128K 上下文）
- 低成本轻量工具：Cloudflare Workers AI（免费额度 generous，适合日活不高场景）
- 多模型路由容灾：本站统一 API 支持「Cerebras → Groq → Mistral」自动降级
四、为什么 Cerebras 能这么快？
Cerebras 使用晶圆级引擎（WSE-3），单芯片集成数万亿晶体管，片上 SRAM 超大，避免 GPU 常见的 HBM 带宽瓶颈；其推理栈针对 Transformer 做了端到端优化，因此 70B 模型也能跑出 2000 t/s 级别的速度。
五、实测方法论（可复现）
- 提示词：固定 50-token 指令 + 要求输出 500 tokens；
- 并发：单连接串行，避免并发干扰；
- 地域：北京出口（Cloudflare/Groq/Cerebras 均走美西节点）；
- 统计：剔除前 10% 和后 10% 极端值，取中位数与四分位区间。
六、榜单更新策略
七、下一步
- 查看《Cerebras 免费推理 API》快速上手；
- 使用本站统一调用 API，一键切换多家免费渠道；
- 关注「榜单」分类，后续将发布成本榜单、质量榜单与区域可用性榜单。
2026 Free AI API Speed Ranking: Cerebras Leads, Groq & Mistral Close Behind
Test period: 2026-08-24 to 2026-08-25, Beijing time; models are each channel's primary free-tier model; sample size n=200 requests/channel.
1. Overall Speed Ranking (output tokens/s, higher is better)
| Rank |
Channel |
Model |
Output speed (tokens/s) |
Time to first token (ms) |
Context limit |
Stability (1–5) |
| 1 |
Cerebras |
Llama 3.3 70B |
1200–2000 |
180–320 |
128K |
4.3 |
| 2 |
Groq |
Llama 3.3 70B |
500–1000 |
220–380 |
128K |
4.6 |
| 3 |
Mistral |
Mistral Small |
300–600 |
260–420 |
32K |
4.5 |
| 4 |
Cloudflare Workers AI |
Llama 3.1 8B |
80–150 |
300–500 |
8K |
4.2 |
| 5 |
Hugging Face Inference |
Meta-Llama-3-8B |
40–90 |
350–600 |
8K |
3.8 |
| 6 |
Together AI (free credits) |
Llama 3.1 70B |
200–400 |
280–450 |
128K |
4.0 |
Note: Together AI's free credits are limited ($25 on signup); once exhausted, it switches to paid. The rest are long-term free tiers.
2. Key Metrics Explained
1) Output speed (tokens/s)
Determines "how long to finish a sentence." For real-time chat/streaming summaries, aim for ≥300 t/s.
2) Time to first token (TTFT)
Determines "how soon you see the first character after clicking." Interactive products should target ≤400ms.
3) Context limit
Long-document processing and multi-turn dialogue benefit from larger context; 128K is better suited for enterprise-grade applications.
4) Stability
Composite score (1–5) based on 7-day availability, rate-limit frequency, and error rates.
3. Scenario-Based Selection Advice
- Real-time chatbots: Cerebras or Groq (speed-first)
- Long-document summarization / RAG: Cerebras / Groq / Together (128K context)
- Low-cost lightweight tools: Cloudflare Workers AI (generous free tier, ideal for lower DAU)
- Multi-model routing for resilience: Our Unified API supports automatic fallback "Cerebras → Groq → Mistral"
4. Why Is Cerebras So Fast?
Cerebras uses the Wafer-Scale Engine (WSE-3), integrating trillions of transistors on a single chip with massive on-chip SRAM, avoiding the HBM bandwidth bottlenecks common in GPUs. Its inference stack is end-to-end optimized for Transformers, enabling 70B models to reach ~2000 t/s.
5. Test Methodology (Reproducible)
- Prompt: fixed 50-token instruction + request for 500-token output;
- Concurrency: single-connection serial requests to avoid interference;
- Region: Beijing egress (Cloudflare/Groq/Cerebras all route to US-West);
- Statistics: trim top/bottom 10% outliers, report median and interquartile range.
6. Update Policy
- Monthly updates (immediate updates for major model/channel changes);
- Submit your实测 data to verify@samai.cc for inclusion in the next edition.
7. Next Steps
- Read "Cerebras Free Inference API" for a quick start;
- Use our Unified API to switch between free channels with one call;
- Follow the "Rankings" category — upcoming editions will cover cost, quality, and regional availability.