DeepSeek V3 0324 vs Step 3.5 Flash
DeepSeek V3 0324 (2025) and Step 3.5 Flash (2026) are frontier reasoning models from DeepSeek and StepFun. DeepSeek V3 0324 ships a 160k-token context window, while Step 3.5 Flash ships a 256k-token context window. On pricing, Step 3.5 Flash costs $0.10/1M input tokens versus $0.27/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Step 3.5 Flash is ~170% cheaper at $0.10/1M; pay for DeepSeek V3 0324 only for provider fit.
Decision scorecard
Local evidence first| Signal | DeepSeek V3 0324 | Step 3.5 Flash |
|---|---|---|
| Best for | provider-routed production | reasoning-heavy apps |
| Decision fit | Coding, Agents, and Long context | Long context |
| Context window | 160k | 256k |
| Cheapest output | $1.12/1M tokens | $0.30/1M tokens |
| Provider routes | 3 tracked | 1 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- DeepSeek V3 0324 has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags DeepSeek V3 0324 for Coding, Agents, and Long context.
- Step 3.5 Flash has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Step 3.5 Flash has the lower cheapest tracked output price at $0.30/1M tokens.
- Step 3.5 Flash uniquely exposes Reasoning in local model data.
- Local decision data tags Step 3.5 Flash for Long context.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
DeepSeek V3 0324
$496
Cheapest tracked route/tier: Novita AI
Step 3.5 Flash
$155
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $341. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for DeepSeek V3 0324 and Step 3.5 Flash; plan for SDK, billing, or endpoint changes.
- Step 3.5 Flash is $0.82/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Step 3.5 Flash adds Reasoning in local capability data.
- No overlapping tracked provider route is sourced for Step 3.5 Flash and DeepSeek V3 0324; plan for SDK, billing, or endpoint changes.
- DeepSeek V3 0324 is $0.82/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Reasoning before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-03-24 | 2026-01-29 |
| Context window | 160k | 256k |
| Parameters | 671B | 196B (11B active) |
| Architecture | decoder only | mixture of experts |
| License | Open Source | Open Source |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | DeepSeek V3 0324 | Step 3.5 Flash |
|---|---|---|
| Input price | $0.27/1M tokens | $0.10/1M tokens |
| Output price | $1.12/1M tokens | $0.30/1M tokens |
| Providers |
Capabilities
| Capability | DeepSeek V3 0324 | Step 3.5 Flash |
|---|---|---|
| Vision | No | No |
| Multimodal | No | No |
| Reasoning | No | Yes |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | No | No |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on reasoning mode: Step 3.5 Flash. Both models share the core language-model surface, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, DeepSeek V3 0324 lists $0.27/1M input and $1.12/1M output tokens on the cheapest tracked provider, while Step 3.5 Flash lists $0.10/1M input and $0.30/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Step 3.5 Flash lower by about $0.37 per million blended tokens. Availability is 3 providers versus 1, so concentration risk also matters.
Choose DeepSeek V3 0324 when provider fit and broader provider choice are central to the workload. Choose Step 3.5 Flash when reasoning depth, larger context windows, and lower input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency.
FAQ
Which has a larger context window, DeepSeek V3 0324 or Step 3.5 Flash?
Step 3.5 Flash supports 256k tokens, while DeepSeek V3 0324 supports 160k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, DeepSeek V3 0324 or Step 3.5 Flash?
Step 3.5 Flash is cheaper on tracked token pricing. DeepSeek V3 0324 costs $0.27/1M input and $1.12/1M output tokens. Step 3.5 Flash costs $0.10/1M input and $0.30/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is DeepSeek V3 0324 or Step 3.5 Flash open source?
DeepSeek V3 0324 is listed under Open Source. Step 3.5 Flash is listed under Open Source. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for reasoning mode, DeepSeek V3 0324 or Step 3.5 Flash?
Step 3.5 Flash has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run DeepSeek V3 0324 and Step 3.5 Flash?
DeepSeek V3 0324 is available on Fireworks AI, Microsoft Foundry, and Novita AI. Step 3.5 Flash is available on OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
When should I pick DeepSeek V3 0324 over Step 3.5 Flash?
Step 3.5 Flash is ~170% cheaper at $0.10/1M; pay for DeepSeek V3 0324 only for provider fit. If your workload also depends on provider fit, start with DeepSeek V3 0324; if it depends on reasoning depth, run the same evaluation with Step 3.5 Flash.
Continue comparing
Last reviewed: 2026-05-29. Data sourced from public model cards and provider documentation.