Claude Opus 5.5 vs DeepSeek V4.1 Flash
At a Glance
| Compare | Claude Opus 5.5Anthropic |  DeepSeek V4.1 FlashDeepSeek |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| CostLower is better · Published-token output estimate | UnrankedNot in the 44-model eligible cohort | #5 of 44$0.022 per LiveBench case |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $4.00Anthropic ↗ · Sep 22, 2026 | $0.15DeepSeek ↗ · Sep 10, 2026 |
| Output priceFrom · USD / 1M tokens | $20.00Anthropic ↗ · Sep 22, 2026 | $0.60Deepinfra ↗ · Sep 23, 2026 |
| Context windowMaximum documented tokens | 1,000K | 1,049K |
| Model facts checked | Sep 22, 2026View model evidence → | Sep 10, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
Side-by-Side Facts
| Field | Claude Opus 5.5 | DeepSeek-V4.1-Flash |
|---|---|---|
| Developer | Anthropic | DeepSeek |
| Family | Claude 5 5 | Deepseek V4 1 |
| Model | Claude Opus 5.5 | DeepSeek-V4.1-Flash |
| Version | Claude Opus 5.5 | DeepSeek-V4.1-Flash |
| Lifecycle | active | active |
| Released | 2026-09-22 | 2026-09-10 |
| Knowledge cutoff | 2026-06-01 | Unknown |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 1,000K | 1,049K |
| Total parameters | Unknown | 763.2B |
| Active parameters | Unknown | Unknown |
| License | Unknown | mit |
| Open weights | No | Yes |
| API available | Yes | Yes |
| Self-hostable | No | Yes |
| Provider access | Anthropic (Standard) | DeepSeek (Standard), Deepinfra (Standard), Together Ai (Standard) |
| Capabilities | chat, generation, reasoning, tools | agents, chat, fim, generation, reasoning, responses, structured_outputs, tools, vision |
| Architecture design | Unknown | Causal Encoder-Decoder (20 encoder + 20 decoder layers) |
| Backbone parameters | Unknown | 552000000000 parameters |
| Message Batches max output (beta) | 300000 tokens | Unknown |
| Active parameters during decode | Unknown | 16000000000 parameters |
| Default effort | medium | Unknown |
| Active parameters during prefill | Unknown | 8000000000 parameters |
| Pre-training corpus | Unknown | 45000000000000 tokens |
| Reasoning effort range | Unknown | 1–100 |
| Retirement commitment | Not sooner than September 22, 2027 | Unknown |
| Routed experts per MoE layer | Unknown | 384 experts |
| Routed experts per token | Unknown | 6 experts |
| Thinking | Adaptive (always on) | Unknown |
| Transformer layers | Unknown | 40 layers |
Claude Opus 5.5 Capabilities
DeepSeek V4.1 Flash Capabilities
Related Comparisons
All image comparisons →| A | Pair | B | Context |
|---|---|---|---|
Claude Opus 5Anthropic | vs | Claude Opus 5.5Anthropic | family variantsimage, text |
Claude Opus 5.5Anthropic | vs | DeepSeek-V4-FlashDeepSeek | cross-developer peerstext |
Claude Opus 5.5Anthropic | vs |  GPT-6 AstraOpenAI | cross-developer peersimage, text |
Claude Fable 5.1Anthropic | vs | Claude Opus 5.5Anthropic | family variantsimage, text |
Claude Opus 5.5Anthropic | vs |  Gemini 3.1 ProGoogle DeepMind | cross-developer peerstext |
Claude Opus 5.5Anthropic | vs | Grok 4.6xAI | cross-developer peersimage, text |
Claude Opus 5.5Anthropic | vs |  Qwen3.8-MaxQwen | cross-developer peersimage, text |
Claude Opus 5.5Anthropic | vs |  Kimi-K3Moonshot AI | cross-developer peersimage, text |
 MiniMax-M3MiniMax | vs | Claude Opus 5.5Anthropic | cross-developer peersimage, text |
Claude Opus 5.5Anthropic | vs |  GLM-5.3Z.ai | cross-developer peerstext |
Claude Opus 5.5Anthropic | vs |  Hy4 previewTencent | cross-developer peerstext |
Claude Opus 5.5Anthropic | vs | Seed 2.1 ProByteDance Seed | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
Claude Opus 5.5 vs DeepSeek V4.1 Flash FAQs
Is Claude Opus 5.5 or DeepSeek V4.1 Flash better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Claude Opus 5.5 and DeepSeek V4.1 Flash, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Claude Opus 5.5 or DeepSeek V4.1 Flash?+
Claude Opus 5.5 is $4.00 and DeepSeek V4.1 Flash is $0.15 per million tokens, so DeepSeek V4.1 Flash is cheaper on this metric. Claude Opus 5.5 is $20.00 and DeepSeek V4.1 Flash is $0.60 per million tokens, so DeepSeek V4.1 Flash is cheaper on this metric.
Which has a larger context window, Claude Opus 5.5 or DeepSeek V4.1 Flash?+
DeepSeek V4.1 Flash has the larger sourced context window. Claude Opus 5.5 supports 1,000K and DeepSeek V4.1 Flash supports 1,049K.
Which performs better in benchmarks, Claude Opus 5.5 or DeepSeek V4.1 Flash?+
There is no overall benchmark winner: At least two independently verified, protocol-matched benchmarks are required for an overall winner.
Can Claude Opus 5.5 or DeepSeek V4.1 Flash be self-hosted?+
DeepSeek V4.1 Flash is the only model in this pair currently marked as self-hostable. Claude Opus 5.5 is not marked open weight; DeepSeek V4.1 Flash is open weight.
Can Claude Opus 5.5 and DeepSeek V4.1 Flash understand images?+
Claude Opus 5.5 is documented with image input; DeepSeek V4.1 Flash is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Claude Opus 5.5 or DeepSeek V4.1 Flash?+
DeepSeek V4.1 Flash has the larger sourced maximum output: Claude Opus 5.5 supports 128K and DeepSeek V4.1 Flash supports 393K output tokens.
Do Claude Opus 5.5 and DeepSeek V4.1 Flash support reasoning and tool use?+
Claude Opus 5.5: reasoning, tool calling, and image input. DeepSeek V4.1 Flash: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Claude Opus 5.5 or DeepSeek V4.1 Flash?+
Claude Opus 5.5 has 1 sourced provider route; DeepSeek V4.1 Flash has 3, so DeepSeek V4.1 Flash has broader tracked availability.
Which offers better value, Claude Opus 5.5 or DeepSeek V4.1 Flash?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.