DeepSeek V3.1 vs Qwen3.5-397B-A17B

Name: DeepSeek V3.1
Author: DeepSeek

DeepSeek V3.1 (2025) and Qwen3.5-397B-A17B (2026) are frontier reasoning models from DeepSeek and Alibaba. DeepSeek V3.1 ships a 64k-token context window, while Qwen3.5-397B-A17B ships a 262k-token context window. On MMLU PRO, Qwen3.5-397B-A17B leads by 4.5 pts. On pricing, DeepSeek V3.1 costs $0.27/1M input tokens versus $0.39/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

DeepSeek V3.1 is ~44% cheaper at $0.27/1M; pay for Qwen3.5-397B-A17B only for reasoning depth.

Decision scorecard

Local evidence first

Signal	DeepSeek V3.1	Qwen3.5-397B-A17B	How to read it
Best for	multimodal apps and provider-routed production	reasoning-heavy apps, multimodal apps, and tool-calling agents	Use-case synthesis from product type, capability flags, context, and provider data.
Decision fit	Coding, Agents, and Vision	Coding, RAG, and Agents	Primary workload tags from local decision data.
Context window	64k	262k	Higher is better when prompts, retrieval chunks, or transcripts are large.
Cheapest output	$1/1M tokens	$2.34/1M tokens	Cheapest tracked provider route; verify your exact region and tier.
Provider routes	8 tracked	4 tracked	Broader coverage can reduce vendor lock-in and fallback risk.
Shared benchmarks	2 shared	MMLU PRO leader	Visible benchmark lead is 4.5 points on MMLU PRO.

Decision tradeoffs

Choose DeepSeek V3.1 when...

DeepSeek V3.1 has the lower cheapest tracked output price at $1/1M tokens.
DeepSeek V3.1 has broader tracked provider coverage for fallback and route flexibility.
DeepSeek V3.1 uniquely exposes Code execution in local model data.
Local decision data tags DeepSeek V3.1 for Coding, Agents, and Vision.

Choose Qwen3.5-397B-A17B when...

Qwen3.5-397B-A17B holds a shared-benchmark lead on MMLU PRO, ahead by 4.5 points.
Qwen3.5-397B-A17B has the larger context window for long prompts, retrieval packs, or transcript analysis.
Qwen3.5-397B-A17B uniquely exposes Reasoning and JSON / Tool use in local model data.
Local decision data tags Qwen3.5-397B-A17B 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 V3.1

Requests / monthInput tokens / requestOutput tokens / request

DeepSeek V3.1

$466

Cheapest tracked route/tier: Novita AI

Qwen3.5-397B-A17B

$897

Cheapest tracked route/tier: OpenRouter

Estimated monthly gap: $431. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

DeepSeek V3.1 -> Qwen3.5-397B-A17B

Provider overlap exists on Together AI and Novita AI; start route-level A/B tests there.
Qwen3.5-397B-A17B is $1.34/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
Check replacement coverage for Code execution before moving production traffic.
Qwen3.5-397B-A17B adds Reasoning and JSON / Tool use in local capability data.

Qwen3.5-397B-A17B -> DeepSeek V3.1

Provider overlap exists on Together AI and Novita AI; start route-level A/B tests there.
DeepSeek V3.1 is $1.34/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
Check replacement coverage for Reasoning and JSON / Tool use before moving production traffic.
DeepSeek V3.1 adds Code execution in local capability data.

Specs

Specification	DeepSeek V3.1 DeepSeek	Qwen3.5-397B-A17B Alibaba
Released	2025-08-21	2026-02-16
Context window	64k	262k
Parameters	671B total, 37B active (MoE)	397B
Architecture	Mixture of Experts	Mixture of Experts
License	MITOSI-approved	Apache 2.0OSI-approved
Openness	Open source	Open source
Weights	Unknown	Available
Code	Unknown	Unknown
Commercial use	Commercial use: permitted	Commercial use: permitted
Knowledge cutoff	-	-

Pricing and availability

Pricing attribute	DeepSeek V3.1	Qwen3.5-397B-A17B
Input price	$0.27/1M tokens	$0.39/1M tokens
Output price	$1/1M tokens	$2.34/1M tokens
Providers	Microsoft Foundry Fireworks AI NVIDIA NIM Together AI AWS Bedrock Replicate API	OpenRouter Together AI Alibaba Cloud PAI-EAS Novita AI

Capabilities

Capability	DeepSeek V3.1	Qwen3.5-397B-A17B
Vision	Yes	Yes
Multimodal	Yes	Yes
Reasoning	No	Yes
JSON / Tool use	No	Yes
Structured outputs	Yes	Yes
Code execution	Yes	No
IDE integration	No	No
Computer use	No	No
Parallel agents	No	No

Benchmarks

Benchmark	DeepSeek V3.1	Qwen3.5-397B-A17B
MMLU PRO	83.3	87.8
SWE-bench Verified	66.0	76.2

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Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.

Both models

DeepSeek V3.1 Qwen3.5-397B-A17B