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Claude Opus 5.5 vs Hy4 Preview

Claude Opus 5.5 grades higher overall (99.5 against 69.3). Hy4 Preview costs 84% less for the same work.

Claude Opus 5.5

by Anthropic · #1 of 67 overall

Coming soon · price at launch
Context
1M
Input / 1M
$4.00
Output / 1M
$20.00

Hy4 Preview

by

Coming soon · price at launch
Context
1M
Input / 1M
$0.83
Output / 1M
$2.50

Better overall

Claude Opus 5.5

Grade 99.5 vs 69.3

Cheaper

Hy4 Preview

84% less, $1.25 vs $8.00 blended

Larger context

Hy4 Preview

1M 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 13, 2026
Claude Opus 5.5Claude Opus 5.5: 1,508
Hy4 PreviewHy4 Preview: —
LMArena WebDevElo-style rating · LMArena (CC BY 4.0) · Oct 13, 2026
LMArena CodingElo-style rating · LMArena (CC BY 4.0) · Oct 13, 2026
Claude Opus 5.5Claude Opus 5.5: 1,545
Hy4 PreviewHy4 Preview: —
SWE-Bench Pro% of tasks resolved · Scale AI SWE-Bench Pro · Sep 22, 2026 · reference
Hy4 PreviewHy4 Preview: —
Terminal-Bench 4.0% of tasks passed · Terminal-Bench · Sep 22, 2026 · reference
Hy4 PreviewHy4 Preview: —
Terminal-Bench 2.1% of tasks passed · Terminal-Bench · Aug 27, 2026 · reference
Claude Opus 5.5Claude Opus 5.5: —

Claude Opus 5.5Hy4 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.

Claude Opus 5.5$1,600 /month
Hy4 Preview$267 /month

Hy4 Preview saves you $1,333 a month at this usage, $15,998 a year.

At a glance

AttributeClaude Opus 5.5Hy4 Preview
Made byAnthropic
AvailabilityComing soonComing soon
Overall gradeExcellent · 99.5Not rated
Overall rank#1 of 67Not ranked
Input price$4.00 per 1M$0.83 per 1M
Output price$20.00 per 1M$2.50 per 1M
Context window1,000,000 tokens1,048,576 tokens
Reasoning levelsYesNo
Reads imagesYesNo
Model IDclaude-opus-5-5hy4-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": "claude-opus-5-5", "messages": [...]}'

# …then swap one word
  -d '{"model": "hy4-preview", "messages": [...]}'

Questions

Is Claude Opus 5.5 or Hy4 Preview better?

Claude Opus 5.5 grades 99.5 against 69.3 for Hy4 Preview, from public benchmarks.

Which is cheaper, Claude Opus 5.5 or Hy4 Preview?

Hy4 Preview: $0.83 in and $2.50 out per million tokens, against $4.00 and $20.00 through FullsendAI.

Which has the larger context window?

Hy4 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, and model makers’ published results where marked v. Prices are FullsendAI’s, per million tokens. Data as of Oct 28, 2026.