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Model comparison

DeepSeek V4 Flash 0731 vs Qwen3.5 0.8B

DeepSeek V4 Flash 0731 (DeepSeek) and Qwen3.5 0.8B (Qwen) side by side: what each costs per million tokens through Rapid Router, how much context each takes, what each supports, and where independent benchmarks place them. Same API, same key; switching is a one-string change.

DeepSeek V4 Flash 0731Qwen3.5 0.8B
Input price per 1M$0.060$0.010
Output price per 1M$0.180$0.050
Context window1M tokens33K tokens
Max output944K tokens8K tokens
Input typestexttext
Capabilitiestools, JSON, reasoningtools
AuthorDeepSeekQwen

What a month costs on each

WorkloadDeepSeek V4 Flash 0731Qwen3.5 0.8B
Chatbot month (15M in, 4M out)$1.62$0.350
RAG month (40M in, 3M out)$2.94$0.550
Coding month (60M in, 10M out)$5.40$1.10

On a typical 75/25 input-output mix, Qwen3.5 0.8B costs less (about 78% less than DeepSeek V4 Flash 0731). DeepSeek V4 Flash 0731 takes the longer prompt at 1M tokens. Try your own numbers in the cost calculator.

Call either one

curl https://rapidrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $RAPIDROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "deepseek/deepseek-v4-flash-0731", "messages": [{"role": "user", "content": "Hello"}]}'

# the other one: change the model string
  -d '{"model": "qwen/qwen3.5-0.8b", ...}'

Common questions

Which is cheaper, DeepSeek V4 Flash 0731 or Qwen3.5 0.8B?

Qwen3.5 0.8B is cheaper on a typical mix of 75% input and 25% output tokens, by about 78%. Through Rapid Router both are billed at the provider list price per million tokens.

Which has the larger context window?

DeepSeek V4 Flash 0731, at 1M tokens. Qwen3.5 0.8B offers 33K tokens.

Can I switch between DeepSeek V4 Flash 0731 and Qwen3.5 0.8B without changing code?

Yes. Both are callable at https://rapidrouter.ai/api/v1 with the same OpenAI-compatible request; only the model string changes (deepseek/deepseek-v4-flash-0731 or qwen/qwen3.5-0.8b).

How do I pay for DeepSeek V4 Flash 0731 or Qwen3.5 0.8B?

Top up a Rapid Router balance by card in US dollars, and both models debit that balance per request.

More DeepSeek models: DeepSeek API pricing · More Qwen: Qwen API pricing