Claude Sonnet 4.5 vs SD 3.5 Medium

Compare Claude Sonnet 4.5 and SD 3.5 Medium: 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 Sonnet 4.5 SD 3.5 Medium
CategoryFrontierImage
Parameters~600B2.5B
Context Window200KN/A
Input Price$0.03/1M tokens$0.003/image/1M tokens
Output Price$0.15/1M tokensN/A/1M tokens
Latency~350ms~2s

Choose Claude Sonnet 4.5 when:

  • ✓ Code generation
  • ✓ Structured output
  • ✓ Automation
Key Strengths:

Strong coding, Better instruction following, Reliable

Choose SD 3.5 Medium when:

  • ✓ General imagery
  • ✓ Batch generation
  • ✓ Prototyping
Key Strengths:

Good quality, Fast, Open weights

Verdict: Claude Sonnet 4.5 vs SD 3.5 Medium

For cost efficiency, SD 3.5 Medium wins at $0.003/image/1M input tokens. For speed, SD 3.5 Medium is faster at ~2s. Claude Sonnet 4.5 excels at Code generation while SD 3.5 Medium is better for General imagery. 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 Sonnet 4.5 costs $0.03/1M input tokens and $0.15/1M output tokens. SD 3.5 Medium costs $0.003/image input and N/A output. SD 3.5 Medium is 10.0x cheaper on input tokens. XALEN offers batch processing at 50% discount on both models.

Performance & Context

Claude Sonnet 4.5 has a 200K context window with ~350ms latency. SD 3.5 Medium offers N/A context at ~2s. Claude Sonnet 4.5 has the larger context window.

Best For

Claude Sonnet 4.5 (Frontier) is optimized for: Code generation, Structured output, Automation. SD 3.5 Medium (Image) works best for: General imagery, Batch generation, Prototyping.

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

# Use SD 3.5 Medium
response_b = client.chat.completions.create(
    model="stable-diffusion-3-5-medium",
    messages=[{"role": "user", "content": "Your question here"}]
)

Start Building with XALEN

200+ AI models. One API. Pay-as-you-go.

Get API Key Try in Playground

Frequently Asked Questions

Which is better, Claude Sonnet 4.5 or SD 3.5 Medium?

Claude Sonnet 4.5 (Frontier, ~600B) offers Strong coding. SD 3.5 Medium (Image, 2.5B) offers Good quality. Choose Claude Sonnet 4.5 for Code generation or SD 3.5 Medium for General imagery.

How much does Claude Sonnet 4.5 cost vs SD 3.5 Medium?

Claude Sonnet 4.5: $0.03/1M input, $0.15/1M output. SD 3.5 Medium: $0.003/image/1M input, N/A/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 Sonnet 4.5 and SD 3.5 Medium 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.