DeepSeek V4 Flash vs Gemini 3.5 Flash

DeepSeek V4 Flash (2026) and Gemini 3.5 Flash (2026) are frontier-tier reasoning models from DeepSeek and Google DeepMind. DeepSeek V4 Flash ships a 1m-token context window, while Gemini 3.5 Flash ships a 1.05m-token context window. On SWE-bench Verified, DeepSeek V4 Flash leads by 1 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

Gemini 3.5 Flash is safer overall; choose DeepSeek V4 Flash when provider fit matters.

Decision scorecard

Local evidence first
SignalDeepSeek V4 FlashGemini 3.5 Flash
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$0.12/1M tokens$9/1M tokens
Provider routes5 tracked4 tracked
Shared benchmarksSWE-bench Verified leader8 shared

Decision tradeoffs

Choose DeepSeek V4 Flash when...
  • DeepSeek V4 Flash holds a shared-benchmark lead on SWE-bench Verified, ahead by 1 points.
  • DeepSeek V4 Flash has the lower cheapest tracked output price at $0.12/1M tokens.
  • DeepSeek V4 Flash has broader tracked provider coverage for fallback and route flexibility.
  • Local decision data tags DeepSeek V4 Flash for Coding, RAG, and Agents.
Choose Gemini 3.5 Flash when...
  • Gemini 3.5 Flash holds a shared-benchmark lead on SWE-bench Pro, ahead by 2.5 points.
  • Gemini 3.5 Flash has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Gemini 3.5 Flash uniquely exposes Vision, Multimodal, and Code execution in local model data.
  • Local decision data tags Gemini 3.5 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

DeepSeek V4 Flash

$76.26

Cheapest tracked route/tier: OpenRouter

Gemini 3.5 Flash

$3,450

Cheapest tracked route/tier: Google AI Studio

Estimated monthly gap: $3,374. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

DeepSeek V4 Flash -> Gemini 3.5 Flash
  • Provider overlap exists on Vercel AI Gateway and OpenRouter; start route-level A/B tests there.
  • Gemini 3.5 Flash is $8.88/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Gemini 3.5 Flash adds Vision, Multimodal, and Code execution in local capability data.
Gemini 3.5 Flash -> DeepSeek V4 Flash
  • Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
  • DeepSeek V4 Flash is $8.88/1M 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.

Specs

Specification
Released2026-04-242026-05-19
Context window1m1.05m
Parameters284B—
ArchitectureMixture of ExpertsDecoder Only
LicenseMITOSI-approvedProprietary
OpennessOpen sourceProprietary
WeightsAvailableNot released
CodeUnknownUnknown
Commercial useCommercial use: permittedCommercial use: conditional
Knowledge cutoff-2025-01

Pricing and availability

Pricing attributeDeepSeek V4 FlashGemini 3.5 Flash
Input price
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.
$1.50/1M tokens
Output price
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.
$9/1M tokens
Providers
DeepSeek PlatformOpenRouterMicrosoft FoundryVercel AI GatewayNovita AI
Google AI StudioGCP Vertex AIVercel AI GatewayOpenRouter

Capabilities

CapabilityDeepSeek V4 FlashGemini 3.5 Flash
VisionNoYes
MultimodalNoYes
ReasoningYesYes
JSON / Tool useYesYes
Structured outputsYesYes
Code executionNoYes
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkDeepSeek V4 FlashGemini 3.5 Flash
SWE-bench Verified79.078.0
SWE-bench Pro52.655.1
Google-Proof Q&A88.192.2
Humanity's Last Exam34.840.2
HumanEval69.592.0
Terminal-Bench 2.056.976.2
MCP-Atlas69.083.6
GeneBench-Pro2.48.1

Continue comparing

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Last reviewed: 2026-07-03. Data sourced from public model cards and provider documentation.