As of August 21, 2026, Grok 4 Fast and Qwen3 VL 4B Instruct have the same blended API cost at $0.70 per 1 million input plus 1 million output tokens. Grok 4 Fast is $0.20 / $0.50 per million tokens versus Qwen3 VL 4B Instruct at $0.10 / $0.60. Sources: https://docs.x.ai/docs/models and https://bailian.console.aliyun.com/
Sources: xAI API pricing (https://docs.x.ai/docs/models); Qwen pricing (https://bailian.console.aliyun.com/)
Grok 4 Fast
xAI
Input
$0.20
Output
$0.50
Qwen3 VL 4B Instruct
Qwen
Input
$0.10
Output
$0.60
Token pricing, specs, and benchmarks side by side
Grok 4 FastQwen3 VL 4B InstructVerdict
Grok 4 Fast offers both lower pricing and stronger benchmark performance across the board, making it the clear value leader in this comparison.
As of August 21, 2026, Grok 4 Fast is 0% cheaper on blended LLM API pricing. Grok 4 Fast costs $0.20 per million input tokens and $0.50 per million output tokens ($0.70 blended 1M-in + 1M-out). Qwen3 VL 4B Instruct costs $0.10 / $0.60 per million tokens ($0.70 blended). Sources: https://docs.x.ai/docs/models and https://bailian.console.aliyun.com/. The cheapest LLM for your app still depends on how many output tokens you generate.
Grok 4 Fast xAI API pricing is $0.20 input and $0.50 output per million tokens via xAI. Qwen3 VL 4B Instruct Qwen API pricing is $0.10 input and $0.60 output per million tokens via Qwen. Use those four numbers, not ChatGPT Plus or Claude Pro subscription prices, when you are comparing APIs.
Grok 4 Fast has a published LiveCodeBench score of 80%. Qwen3 VL 4B Instruct does not have that eval on this page yet.
Grok 4 Fast supports a 2M token context window, while Qwen3 VL 4B Instruct supports 262K tokens. Grok 4 Fast offers a larger context window. Filling a larger window bills more input tokens, so the cheaper-per-million model can still cost more on long documents.
Grok 4 Fast leads on 2 of 2 shared benchmarks versus Qwen3 VL 4B Instruct's 0 wins. Check the comparison table for GPQA Diamond, SWE-bench, MMLU, HLE, and the other evals we track. Token price and benchmark score together are the usual LLM comparison, not either number alone.
Both Grok 4 Fast and Qwen3 VL 4B Instruct are production API models. For cost-sensitive production traffic, Grok 4 Fast has better economics on the blended 1M-in + 1M-out scale. For maximum capability, weight the benchmark table for your domain. Many production stacks route cheap models for drafts and a frontier model for the hard turn, which is usually cheaper than sending everything to the expensive API.
Yes. Call Grok 4 Fast through xAI and Qwen3 VL 4B Instruct through Qwen with separate API keys, or through a gateway that already wraps both. Keep prompts in tokens, not characters, when you estimate the invoice. AnotherWrapper templates can swap providers without rewriting auth and billing.
List rates are the latest published xAI API pricing and Qwen API pricing, quoted per million tokens. Official rate sheets: https://docs.x.ai/docs/models and https://bailian.console.aliyun.com/. Prompt caching, batch APIs, and committed-use discounts can change the invoice. Benchmark scores are from official publications and independent evals, updated as new numbers land.
Grok 4 Fast supports up to 30K output tokens per request, while Qwen3 VL 4B Instruct supports up to 262K output tokens. Output tokens are usually the expensive half of API pricing, so a higher max output cap is a capability, not a discount.
Grok 4 Fast has a measured throughput of approximately 90 tokens/second. Throughput data for Qwen3 VL 4B Instruct is not yet available. Throughput (tokens per second) and time-to-first-token are why two models with the same per-million-token price can still feel different in chat and agents.
Use the model pickers at the top of this LLM comparison. Search any model in the index and the URL updates. Open Grok 4 Fast or Qwen3 VL 4B Instruct from the sidebar for the single-model API pricing page, or go back to the LLM pricing table to sort by cheapest blended cost.
This comparison covers API pricing, context window, throughput, and benchmark scores. Grok 4 Fast costs $0.20/M input and $0.50/M output. Qwen3 VL 4B Instruct costs $0.10/M input and $0.60/M output.
Rank both on the LLM leaderboard, SWE-bench, and Humanity's Last Exam.
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