LLM Reference

DeepSeek V4 Pro vs GPT-5.6 Sol

GPT-5.6 Sol and DeepSeek V4 Pro compare OpenAI's closed July 2026 GA frontier route with DeepSeek's open-weight long-context text model. Sol is built for OpenAI-hosted agentic, multimodal, and cyber workloads with 1.05M context and July launch-table evidence. DeepSeek V4 Pro offers downloadable weights, very low API pricing, and 1M text-only context for teams that prioritize cost and deployment control.

Pick GPT-5.6 Sol when you need OpenAI integration, multimodal input, max reasoning effort, and the strongest first-party agent/cyber/science launch rows. Pick DeepSeek V4 Pro when open weights, self-hosting or weight inspection, and extremely low token prices matter more than closed-service frontier features. Keep modality discipline: DeepSeek V4 Pro is text-only in local seed data.

Decision scorecard

Local evidence first
SignalDeepSeek V4 ProGPT-5.6 Sol
Best forreasoning-heavy apps, tool-calling agents, and long-context analysisreasoning-heavy apps, multimodal apps, and tool-calling agents
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window1m1.05m
Cheapest output$0.87/1M tokens$30/1M tokens
Provider routes5 tracked2 tracked
Shared benchmarks4 sharedSWE-bench Pro leader

Decision tradeoffs

Choose DeepSeek V4 Pro when...
  • DeepSeek V4 Pro has the lower cheapest tracked output price at $0.87/1M tokens.
  • DeepSeek V4 Pro has broader tracked provider coverage for fallback and procurement flexibility.
  • DeepSeek V4 Pro uniquely exposes Structured outputs in local model data.
  • Local decision data tags DeepSeek V4 Pro for Coding, RAG, and Agents.
Choose GPT-5.6 Sol when...
  • GPT-5.6 Sol holds a shared-benchmark lead on SWE-bench Pro, ahead by 9.2 points.
  • GPT-5.6 Sol has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • GPT-5.6 Sol uniquely exposes Vision, Multimodal, and Code execution in local model data.
  • Local decision data tags GPT-5.6 Sol 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 Pro

DeepSeek V4 Pro

$566

Cheapest tracked route/tier: DeepSeek Platform

GPT-5.6 Sol

$11,500

Cheapest tracked route/tier: OpenAI API 0-272K input tokens

Estimated monthly gap: $10,935. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

DeepSeek V4 Pro -> GPT-5.6 Sol
  • Provider overlap exists on OpenRouter; start route-level A/B tests there.
  • GPT-5.6 Sol is $29.13/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Check replacement coverage for Structured outputs before moving production traffic.
  • GPT-5.6 Sol adds Vision, Multimodal, and Code execution in local capability data.
GPT-5.6 Sol -> DeepSeek V4 Pro
  • Provider overlap exists on OpenRouter; start route-level A/B tests there.
  • DeepSeek V4 Pro is $29.13/1M 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 Pro adds Structured outputs in local capability data.

Specs

Specification
Released2026-04-242026-07-09
Context window1m1.05m
Parameters1.6T
ArchitectureMixture of ExpertsDecoder Only
LicenseMITOSI-approvedProprietary
OpennessOpen sourceProprietary
WeightsAvailableNot released
CodeUnknownUnknown
Commercial useCommercial use: permittedCommercial use: conditional
Knowledge cutoff--

Pricing and availability

Pricing attributeDeepSeek V4 ProGPT-5.6 Sol
Input price$0.43/1M tokens
0-272K input tokens
$5/1M tokens
Standard GPT-5.6 Sol token pricing before the long-context surcharge threshold.
272K+ input tokens
$10/1M tokens
Long-context surcharge applies above 272K input tokens for the full request.
Output price$0.87/1M tokens
0-272K input tokens
$30/1M tokens
Standard GPT-5.6 Sol token pricing before the long-context surcharge threshold.
272K+ input tokens
$45/1M tokens
Long-context surcharge applies above 272K input tokens for the full request.
Providers

Capabilities

CapabilityDeepSeek V4 ProGPT-5.6 Sol
VisionNoYes
MultimodalNoYes
ReasoningYesYes
Function callingYesYes
Tool useYesYes
Structured outputsYesNo
Code executionNoYes
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkDeepSeek V4 ProGPT-5.6 Sol
SWE-bench Pro55.464.6
Google-Proof Q&A90.194.6
GeneBench-Pro2.431.5
BrowseComp83.490.4

Deep dive

Deployment model is the first split. GPT-5.6 Sol is a closed OpenAI-hosted frontier service across ChatGPT, Codex, and the API. DeepSeek V4 Pro is open-weight with Hugging Face checkpoint access and low-cost DeepSeek API pricing.

Cost can favor DeepSeek V4 Pro dramatically on token economics, but Sol adds multimodal input, OpenAI tool ecosystems, and July 2026 GA launch rows that text-only open-weight routes cannot match one-for-one.

Benchmark comparisons need harness labels and modality guards. Use OpenAI GA rows for Sol and DeepSeek-specific rows for V4 Pro. Do not compare image or multimodal tasks as if DeepSeek V4 Pro supports them.

For teams choosing between frontier closed service and open-weight efficiency, run route-level tests on coding agents, long-context retrieval, and total cost of ownership including hosting or provider fees.

FAQ

Which model is open weight?

DeepSeek V4 Pro is tracked as open-weight with a public Hugging Face checkpoint. GPT-5.6 Sol is proprietary and available through OpenAI-hosted routes only.

Which model is cheaper to run?

DeepSeek V4 Pro is generally much cheaper on tracked API pricing and can be self-hosted from open weights. GPT-5.6 Sol uses OpenAI frontier pricing with batch, cache, and long-context surcharges that should be modeled on your real prompt length.

Does DeepSeek V4 Pro support images?

No in the local seed. DeepSeek V4 Pro is tracked as text-only, while GPT-5.6 Sol supports multimodal input. Do not use Sol multimodal benchmark or capability claims as DeepSeek evidence.

Which model is stronger for coding agents?

Compare source-labeled coding rows and your own harness. GPT-5.6 Sol has July 2026 OpenAI GA agent and coding launch evidence. DeepSeek V4 Pro has strong cost-efficient coding rows in the seed, but the final choice depends on deployment control, modality needs, and acceptance-test quality.

Continue comparing

Last reviewed: 2026-07-09. Data sourced from public model cards and provider documentation.