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DeepSeek V4 Flash vs Qwen3.5 9B

DeepSeek V4 Flash has the stronger public benchmark scores. They cost the same.

DeepSeek V4 Flash

by DeepSeek · #27 of 67 overall

Coming soon · price at launch
Context
1M
Input / 1M
$0.090
Output / 1M
$0.18

Qwen3.5 9B

by Qwen

Coming soon · price at launch
Context
256K
Input / 1M
$0.10
Output / 1M
$0.15

Better overall

DeepSeek V4 Flash

Grade 72.1 vs —

Cheaper

Same price

Both $0.11 blended

Larger context

DeepSeek V4 Flash

1M vs 256K 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 15, 2026
DeepSeek V4 FlashDeepSeek V4 Flash: 1,436
Qwen3.5 9BQwen3.5 9B: —
LMArena WebDevElo-style rating · LMArena (CC BY 4.0) · Oct 13, 2026
DeepSeek V4 FlashDeepSeek V4 Flash: 1,582
Qwen3.5 9BQwen3.5 9B: —
LMArena CodingElo-style rating · LMArena (CC BY 4.0) · Oct 15, 2026
DeepSeek V4 FlashDeepSeek V4 Flash: 1,484
Qwen3.5 9BQwen3.5 9B: —
SWE-bench Verified% of issues resolved · SWE-bench · Apr 22, 2026 · reference
DeepSeek V4 FlashDeepSeek V4 Flash: 79%v
Qwen3.5 9BQwen3.5 9B: —
SWE-Bench Pro% of tasks resolved · Scale AI SWE-Bench Pro · Apr 22, 2026 · reference
DeepSeek V4 FlashDeepSeek V4 Flash: 52.6%v
Qwen3.5 9BQwen3.5 9B: —
Terminal-Bench 2.0% of tasks passed · Terminal-Bench · Apr 22, 2026 · reference
DeepSeek V4 FlashDeepSeek V4 Flash: 56.9%v
Qwen3.5 9BQwen3.5 9B: —
LiveCodeBenchpass@1, % · LiveCodeBench · Apr 22, 2026 · reference

DeepSeek V4 FlashQwen3.5 9Bv = 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.

DeepSeek V4 Flash$25.20 /month
Qwen3.5 9B$26.00 /month

DeepSeek V4 Flash saves you $0.80 a month at this usage, $9.60 a year.

At a glance

AttributeDeepSeek V4 FlashQwen3.5 9B
Made byDeepSeekQwen
AvailabilityComing soonComing soon
Overall gradeExcellent · 72.1Not rated
Overall rank#27 of 67Not ranked
Input price$0.090 per 1M$0.10 per 1M
Output price$0.18 per 1M$0.15 per 1M
Context window1,048,576 tokens262,144 tokens
Reasoning levelsNoYes
Reads imagesNoYes
Model IDdeepseek-v4-flashqwen3.5-9b

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": "deepseek-v4-flash", "messages": [...]}'

# …then swap one word
  -d '{"model": "qwen3.5-9b", "messages": [...]}'

Questions

Is DeepSeek V4 Flash or Qwen3.5 9B better?

One of them doesn’t have enough public benchmark scores to be graded yet; compare the benchmarks both have above.

Which is cheaper, DeepSeek V4 Flash or Qwen3.5 9B?

DeepSeek V4 Flash: $0.090 in and $0.18 out per million tokens, against $0.10 and $0.15 through FullsendAI.

Which has the larger context window?

DeepSeek V4 Flash, 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), SWE-bench, 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.