LLM Reference

Claude Opus 4.5 vs DeepSeek V4 Flash

Claude Opus 4.5 (2025) and DeepSeek V4 Flash (2026) are frontier-tier reasoning models from Anthropic and DeepSeek. Claude Opus 4.5 ships a 200k-token context window, while DeepSeek V4 Flash ships a 1m-token context window. On MMLU PRO, Claude Opus 4.5 leads by 2.5 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

DeepSeek V4 Flash fits 5x more tokens; pick it for long-context work and Claude Opus 4.5 for tighter calls.

Decision scorecard

Local evidence first
SignalClaude Opus 4.5DeepSeek V4 Flash
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsreasoning-heavy apps, tool-calling agents, and long-context analysis
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window200k1m
Cheapest output$25/1M tokens$0.12/1M tokens
Provider routes6 tracked5 tracked
Shared benchmarksMMLU PRO leader5 shared

Decision tradeoffs

Choose Claude Opus 4.5 when...
  • Claude Opus 4.5 holds a shared-benchmark lead on MMLU PRO, ahead by 2.5 points.
  • Claude Opus 4.5 has broader tracked provider coverage for fallback and route flexibility.
  • Claude Opus 4.5 uniquely exposes Vision, Multimodal, and Code execution in local model data.
  • Local decision data tags Claude Opus 4.5 for Coding, RAG, and Agents.
Choose DeepSeek V4 Flash when...
  • DeepSeek V4 Flash holds a shared-benchmark lead on SWE-bench Pro, ahead by 10.8 points.
  • DeepSeek V4 Flash has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • DeepSeek V4 Flash has the lower cheapest tracked output price at $0.12/1M tokens.
  • Local decision data tags DeepSeek V4 Flash for Coding, RAG, and Agents.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Lower estimate DeepSeek V4 Flash

Claude Opus 4.5

$10,250

Cheapest tracked route/tier: Microsoft Foundry

DeepSeek V4 Flash

$76.26

Cheapest tracked route/tier: OpenRouter

Estimated monthly gap: $10,174. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude Opus 4.5 -> DeepSeek V4 Flash
  • Provider overlap exists on OpenRouter, Microsoft Foundry, and Vercel AI Gateway; start route-level A/B tests there.
  • DeepSeek V4 Flash is $24.88/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Check replacement coverage for Vision, Multimodal, and Code execution before moving production traffic.
DeepSeek V4 Flash -> Claude Opus 4.5
  • Provider overlap exists on Microsoft Foundry, OpenRouter, and Vercel AI Gateway; start route-level A/B tests there.
  • Claude Opus 4.5 is $24.88/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Claude Opus 4.5 adds Vision, Multimodal, and Code execution in local capability data.

Specs

Specification
Released2025-11-012026-04-24
Context window200k1m
Parameters—284B
ArchitectureDecoder OnlyMixture of Experts
LicenseProprietaryMITOSI-approved
OpennessProprietaryOpen source
WeightsNot releasedAvailable
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: permitted
Knowledge cutoff2025-12-

Pricing and availability

Pricing attributeClaude Opus 4.5DeepSeek V4 Flash
Input price$5/1M tokens
Off-peak
$0.22/1M tokens
All UTC hours outside DeepSeek's peak windows. Cache-hit input: $0.007 per 1M tokens; cache-miss input: $0.22 per 1M; output: $0.66 per 1M.
Peak
$0.44/1M tokens
01:00-04:00 and 06:00-10:00 UTC. Cache-hit input: $0.014 per 1M tokens; cache-miss input: $0.44 per 1M; output: $1.32 per 1M.
Output price$25/1M tokens
Off-peak
$0.66/1M tokens
All UTC hours outside DeepSeek's peak windows. Cache-hit input: $0.007 per 1M tokens; cache-miss input: $0.22 per 1M; output: $0.66 per 1M.
Peak
$1.32/1M tokens
01:00-04:00 and 06:00-10:00 UTC. Cache-hit input: $0.014 per 1M tokens; cache-miss input: $0.44 per 1M; output: $1.32 per 1M.
Providers
Microsoft FoundryAnthropicGCP Vertex AIAWS BedrockOpenRouterVercel AI Gateway
DeepSeek PlatformOpenRouterMicrosoft FoundryVercel AI GatewayNovita AI

Capabilities

CapabilityClaude Opus 4.5DeepSeek V4 Flash
VisionYesNo
MultimodalYesNo
ReasoningYesYes
JSON / Tool useYesYes
Structured outputsYesYes
Code executionYesNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkClaude Opus 4.5DeepSeek V4 Flash
MMLU PRO88.986.4
SWE-bench Verified80.979.0
SWE-bench Pro41.852.6
Google-Proof Q&A87.088.1
Chatbot Arena1466.01437.0

Continue comparing

Model pages
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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.