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Qwen3.8 27B vs Step 5 Preview

Close to a tie overall. Qwen3.8 27B costs 46% less for the same work.

Qwen3.8 27B

by Qwen · #25 of 67 overall

Coming soon · price at launch
Context
256K
Input / 1M
$0.20
Output / 1M
$2.50

Step 5 Preview

by StepFun · #24 of 67 overall

Coming soon · price at launch
Context
1M
Input / 1M
$1.00
Output / 1M
$2.70

Better overall

About even

Grade 74.4 vs 75.2

Cheaper

Qwen3.8 27B

46% less, $0.78 vs $1.43 blended

Larger context

Step 5 Preview

256K vs 1M tokens

Head to head

Public benchmarks. Longer is better; each value links to its source.

LMArena TextElo-style rating · LMArena (CC BY 4.0) · Oct 28, 2026
LMArena WebDevElo-style rating · LMArena (CC BY 4.0) · Oct 13, 2026
LMArena CodingElo-style rating · LMArena (CC BY 4.0) · Oct 28, 2026
SWE-Bench Pro% of tasks resolved · Scale AI SWE-Bench Pro · Aug 5, 2026 · reference
Step 5 PreviewStep 5 Preview: —
Terminal-Bench 4.0% of tasks passed · Terminal-Bench · Sep 20, 2026 · reference
Qwen3.8 27BQwen3.8 27B: —
Terminal-Bench 2.1% of tasks passed · Terminal-Bench · Aug 5, 2026 · reference
Step 5 PreviewStep 5 Preview: —
LiveCodeBenchpass@1, % · LiveCodeBench · Aug 5, 2026 · reference
Step 5 PreviewStep 5 Preview: —

Qwen3.8 27BStep 5 Previewv = reported by the model’s maker. — = no public score yet. Arena bars span the range across every model we grade.

What it costs you

Drag to match your monthly usage.

Qwen3.8 27B$140 /month
Step 5 Preview$308 /month

Qwen3.8 27B saves you $168 a month at this usage, $2,016 a year.

At a glance

AttributeQwen3.8 27BStep 5 Preview
Made byQwenStepFun
AvailabilityComing soonComing soon
Overall gradeExcellent · 74.4Excellent · 75.2
Overall rank#25 of 67#24 of 67
Input price$0.20 per 1M$1.00 per 1M
Output price$2.50 per 1M$2.70 per 1M
Context window262,144 tokens1,048,576 tokens
Reasoning levelsYesNo
Reads imagesYesYes
Model IDqwen3.8-27bstep-5-preview

Try both with one key

Same endpoint, same key, both hosted in the USA. Change one word to switch models, in Claude Code, Cursor, Cline or your own code.

Get your API key
# Ask either model the same thing
curl https://fullsendai.com/v1/chat/completions \
  -H "Authorization: Bearer $FULLSEND_API_KEY" \
  -d '{"model": "qwen3.8-27b", "messages": [...]}'

# …then swap one word
  -d '{"model": "step-5-preview", "messages": [...]}'

Questions

Is Qwen3.8 27B or Step 5 Preview better?

They grade within two points of each other (74.4 and 75.2), so pick on price and the benchmarks that match your work.

Which is cheaper, Qwen3.8 27B or Step 5 Preview?

Qwen3.8 27B: $0.20 in and $2.50 out per million tokens, against $1.00 and $2.70 through FullsendAI.

Which has the larger context window?

Step 5 Preview, with 1,048,576 tokens.

Can I use both with one API key?

Yes, once they launch: both are coming soon, at the prices shown, and both will use the same FullsendAI key.

Model rankingsAll benchmarksCompare other models

Scores: LMArena (CC BY 4.0), Scale AI SWE-Bench Pro, Terminal-Bench, LiveCodeBench, and model makers’ published results where marked v. Prices are FullsendAI’s, per million tokens. Data as of Oct 28, 2026.