Claude Opus 4.5 vs Mistral Small 3.1

Compare Claude Opus 4.5 and Mistral Small 3.1: pricing, performance, context window, latency, and best use cases. Side-by-side comparison on XALEN.

Updated 2026-05-21 · By Abhishek Raj · Our methodology

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Feature Claude Opus 4.5 Mistral Small 3.1
CategoryFrontierCompact
Parameters~2.5T24B
Context Window200K128K
Input Price$0.15/1M tokens$0.02/1M tokens
Output Price$0.75/1M tokens$0.04/1M tokens
Latency~900ms~120ms

Choose Claude Opus 4.5 when:

  • ✓ Creative writing
  • ✓ Complex analysis
  • ✓ Research
Key Strengths:

Superior creativity, Nuanced reasoning, Complex analysis

Choose Mistral Small 3.1 when:

  • ✓ Lightweight tasks
  • ✓ Classification
  • ✓ Simple generation
Key Strengths:

128K context, Low cost, Fast

Verdict: Claude Opus 4.5 vs Mistral Small 3.1

For cost efficiency, Mistral Small 3.1 wins at $0.02/1M input tokens. For speed, Mistral Small 3.1 is faster at ~120ms. Claude Opus 4.5 excels at Creative writing while Mistral Small 3.1 is better for Lightweight tasks. Both are available on XALEN through a single API — try them in the Playground to see which fits your workload.

Detailed Analysis

Pricing Comparison

Claude Opus 4.5 costs $0.15/1M input tokens and $0.75/1M output tokens. Mistral Small 3.1 costs $0.02 input and $0.04 output. Mistral Small 3.1 is 7.5x cheaper on input tokens. XALEN offers batch processing at 50% discount on both models.

Performance & Context

Claude Opus 4.5 has a 200K context window with ~900ms latency. Mistral Small 3.1 offers 128K context at ~120ms. Claude Opus 4.5 has the larger context window.

Best For

Claude Opus 4.5 (Frontier) is optimized for: Creative writing, Complex analysis, Research. Mistral Small 3.1 (Compact) works best for: Lightweight tasks, Classification, Simple generation.

Try Both on XALEN

Both models are available through XALEN's OpenAI-compatible API. Switch between them by changing the model parameter:

from xalen import XALEN

client = XALEN(api_key="xln_test_YOUR_KEY")

# Use Claude Opus 4.5
response_a = client.chat.completions.create(
    model="claude-opus-4-5",
    messages=[{"role": "user", "content": "Your question here"}]
)

# Use Mistral Small 3.1
response_b = client.chat.completions.create(
    model="mistral-small-3-1",
    messages=[{"role": "user", "content": "Your question here"}]
)

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Get API Key Try in Playground

Frequently Asked Questions

Which is better, Claude Opus 4.5 or Mistral Small 3.1?

Claude Opus 4.5 (Frontier, ~2.5T) offers Superior creativity. Mistral Small 3.1 (Compact, 24B) offers 128K context. Choose Claude Opus 4.5 for Creative writing or Mistral Small 3.1 for Lightweight tasks.

How much does Claude Opus 4.5 cost vs Mistral Small 3.1?

Claude Opus 4.5: $0.15/1M input, $0.75/1M output. Mistral Small 3.1: $0.02/1M input, $0.04/1M output. Both available on XALEN with batch processing at 50% discount.

Can I use both models on XALEN?

Yes. XALEN provides 200+ models through a single OpenAI-compatible API. Switch between Claude Opus 4.5 and Mistral Small 3.1 by changing the model parameter. No code changes needed.

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Last updated: 2026-05-21. Pricing and specifications may change. Check pricing page for latest rates.