DeepSeek's models, from V3.2 to the newer V4 and V4.1 families, are among the most popular open models for coding, reasoning and everyday chat. To use them in your own app you need an API key. There are two common ways to get one.
Option 1: Get a key directly from DeepSeek
- Create an account on DeepSeek's developer platform.
- Add a payment method and top up your balance.
- Open the API keys section and create a new key.
- Call DeepSeek's API with that key.
This works well if you only ever plan to use DeepSeek models. The trade-off: every other model provider (Z.ai for GLM, Moonshot for Kimi, Alibaba for Qwen…) needs its own account, its own billing and its own key.
Option 2: Use one key for DeepSeek and every other model
A model router gives you one API key that works for many model makers. With Solo Router:
- Sign in with Google. New accounts get free credit to try things out.
- Your first API key is created automatically on the Keys page. Copy it.
- Send a request:
curl https://solorouter.ai/api/v1/chat/completions \
-H "Authorization: Bearer $SOLO_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "deepseek/deepseek-v4.1-flash",
"messages": [{"role": "user", "content": "Hello"}]}'
To switch to another model, change one string, for example z-ai/glm-5.3 or moonshotai/kimi-k3.
Which DeepSeek model should you pick?
| Model | Input / 1M tokens | Output / 1M tokens | Good for |
|---|---|---|---|
| DeepSeek V4.1 Flash | $0.39 | $1.56 | Best default: fast, reasoning, 1M context |
| DeepSeek V4 Flash | $0.182 | $0.364 | Cheapest for high volume |
| DeepSeek V4 Pro | $2.262 | $4.524 | Hardest tasks |
| DeepSeek V3.2 | $0.65 | $2.08 | Older, well-known behaviour |
Prices are Solo Router's current prices; see the live list on the DeepSeek API page.
Keep your key safe
- Never put the key in front-end code or a public repository.
- Use a separate key per app, so you can revoke one without breaking the others.
- On Solo Router you can give each key a spending limit, which caps the damage if a key ever leaks.
Using the key in your tools
Most AI tools (LangChain, Cline, Continue, Open WebUI, LibreChat) have a "base URL" or "custom provider" setting. Set the base URL to https://solorouter.ai/api/v1, paste your key and type the model ID. See the docs for more examples.