Cerebras 免费推理 API：晶圆级芯片极速推理，零成本上手
Cerebras Systems 以「晶圆级引擎（WSE）」芯片闻名——把整块晶圆做成一颗处理器，专门为大模型推理加速。其 Inference API 提供免费层，让你零成本体验目前市面上最快的开源模型推理之一。
一、免费层能拿到什么
| 项目 |
说明 |
| 免费模型 |
Llama 3.3 70B Instruct（主力）、Llama 3.1 8B |
| 输出速度 |
实测 1200–2000 tokens/s（70B 模型），远超 GPU 集群方案 |
| 上下文 |
128K tokens |
| 速率限制 |
免费层约 1 请求/秒、每分钟 60 请求（以控制台实时显示为准） |
| 费用 |
$0，无需信用卡 |
提示：Cerebras 免费层的定位是「开发者体验 + 评估」，适合原型验证和轻量生产流量，不适合高并发生产主力。
二、注册与获取 API Key（约 1 分钟）
- 打开 Cerebras 控制台（console.cerebras.ai），用邮箱或 Google 账号注册；
- 进入 API Keys 页面，点击 Create Key，复制保存；
- 控制台首页可直接在线 Playground 试跑，无需写代码。
整个过程无需信用卡、无需企业认证。
三、API 调用示例
Cerebras 的 API 完全兼容 OpenAI 格式，只需替换 base_url：
from openai import OpenAI
client = OpenAI(
base_url="https://api.cerebras.ai/v1",
api_key="你的Cerebras API Key",
)
resp = client.chat.completions.create(
model="llama-3.3-70b",
messages=[
{"role": "user", "content": "用一句话解释什么是晶圆级芯片"}
],
max_tokens=256,
)
print(resp.choices[0].message.content)
cURL 版本：
curl https://api.cerebras.ai/v1/chat/completions \
-H "Authorization: Bearer 你的API Key" \
-H "Content-Type: application/json" \
-d '{
"model": "llama-3.3-70b",
"messages": [{"role": "user", "content": "Hello"}],
"max_tokens": 128
}'
四、速率限制与应对
- 触发限流会返回
429，响应头中带有 Retry-After；
- 建议实现指数退避重试（参考本站《统一调用 API》分类中的失败重试与降级策略）；
- 高并发场景可搭配 Groq / Mistral 免费层做多渠道路由（本站统一 API 已内置该能力）。
五、适用场景
- 极速原型验证：需要 70B 级模型质量 + 秒级响应的 Demo；
- 长文本流式输出：128K 上下文 + 高吞吐，适合实时摘要、对话；
- 成本敏感型轻量生产：配合限流策略，日请求量不大的工具类应用。
六、与其他免费渠道对比
| 渠道 |
代表模型 |
输出速度（实测） |
上下文 |
| Cerebras |
Llama 3.3 70B |
1200–2000 t/s |
128K |
| Groq |
Llama 3.3 70B |
500–1000 t/s |
128K |
| Mistral |
Mistral Small |
300–600 t/s |
32K |
| Cloudflare Workers AI |
Llama 3.1 8B |
80–150 t/s |
8K |
完整横评见本站《2026 免费 AI API 速度榜单》。
七、常见问题
Q：免费层会突然收费吗？
A：Cerebras 有明确的免费/付费分层，免费 Key 与付费 Key 隔离，不会静默扣费。
Q：支持 function calling 吗？
A：支持，OpenAI 兼容的 tools 参数可直接使用。
Q：可以商用吗？
A：免费层输出可用于开发评估；商用生产建议升级到付费层以获得 SLA 保障。
Cerebras Free Inference API: Web-Scale Chip Speed, Zero-Cost to Start
Cerebras Systems is known for its Web-Scale Engine (WSE) — a wafer-scale processor built specifically to accelerate LLM inference. Its Inference API offers a free tier so you can experience some of the fastest open-model inference available today, at zero cost.
1. What the Free Tier Includes
| Item |
Details |
| Free models |
Llama 3.3 70B Instruct (main), Llama 3.1 8B |
| Output speed |
Measured 1200–2000 tokens/s (70B), far faster than typical GPU clusters |
| Context |
128K tokens |
| Rate limits |
~1 req/s, 60 req/min on the free tier (see console for live values) |
| Cost |
$0, no credit card required |
Note: the Cerebras free tier is positioned for developer experience and evaluation — great for prototyping and light production traffic, not for high-concurrency production workloads.
2. Sign Up & Get an API Key (~1 minute)
- Open the Cerebras console (console.cerebras.ai) and sign up with email or Google;
- Go to API Keys and create a key — copy and store it safely;
- Try the built-in Playground on the console home page, no code needed.
No credit card, no enterprise verification.
3. API Call Examples
The Cerebras API is fully OpenAI-compatible — just swap the base_url:
from openai import OpenAI
client = OpenAI(
base_url="https://api.cerebras.ai/v1",
api_key="YOUR_CEREBRAS_API_KEY",
)
resp = client.chat.completions.create(
model="llama-3.3-70b",
messages=[{"role": "user", "content": "Explain wafer-scale chips in one sentence"}],
max_tokens=256,
)
print(resp.choices[0].message.content)
cURL version:
curl https://api.cerebras.ai/v1/chat/completions \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "llama-3.3-70b", "messages": [{"role": "user", "content": "Hello"}], "max_tokens": 128}'
4. Rate Limits & Mitigation
- Rate-limited requests return
429 with a Retry-After header;
- Implement exponential backoff (see our Unified API category for retry & fallback strategies);
- For high concurrency, route across Groq / Mistral free tiers — APIShare's unified API has this built in.
5. Best Use Cases
- Rapid prototyping: 70B-class quality with second-level response times;
- Long-context streaming: 128K context + high throughput for real-time summarization and chat;
- Cost-sensitive light production: tool-style apps with modest daily request volume.
6. Comparison with Other Free Channels
| Channel |
Representative model |
Output speed (measured) |
Context |
| Cerebras |
Llama 3.3 70B |
1200–2000 t/s |
128K |
| Groq |
Llama 3.3 70B |
500–1000 t/s |
128K |
| Mistral |
Mistral Small |
300–600 t/s |
32K |
| Cloudflare Workers AI |
Llama 3.1 8B |
80–150 t/s |
8K |
See our "2026 Free AI API Speed Ranking" for the full benchmark.
7. FAQ
Q: Can the free tier suddenly start charging me?
A: Cerebras keeps free and paid keys strictly separated — no silent billing.
Q: Does it support function calling?
A: Yes, the OpenAI-compatible tools parameter works as-is.
Q: Is commercial use allowed?
A: Free-tier outputs are fine for development and evaluation; for production commercial use, upgrade to the paid tier for SLA guarantees.