The AI arena is free today

Open Superagent

DeepSeek-V4-Pro-0813 vs Step-3.5-Flash

Comparing DeepSeek-V4-Pro-0813 and Step-3.5-Flash across benchmarks, pricing, and capabilities.

DeepSeek · StepFun · Updated for 2026

Which is better?

DeepSeek-V4-Pro-0813 and Step-3.5-Flash trade strengths across price, capabilities, and technical limits. The better choice depends on the workload.

On price, Step-3.5-Flash is roughly 3.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

DeepSeek-V4-Pro-0813 also accepts a larger context window (1,048,576 input tokens), making it the stronger choice for long documents and large codebases.

Based on current benchmark, pricing, and model metadata for 2026.

Choose DeepSeek-V4-Pro-0813

  • you process long inputs — it offers a 1,048,576 token context window
  • you want the most recent training data — it shipped Aug 2026

Choose Step-3.5-Flash

  • cost matters — it's about 3.1x cheaper per token

At a glance

The differences that matter most.

DeepSeek-V4-Pro-0813
DeepSeek
Step-3.5-Flash
StepFun
Benchmark wins
—
—
Input price
$0.43 / M
$0.10 / M
Output price
$0.87 / M
$0.40 / M
Context window
1,048,576
65,536
Released
Aug 2026
Feb 2026
License
MIT
Apache 2.0

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

DeepSeek-V4-Pro-0813 and Step-3.5-Flashdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Playground indexes and blind preference scores

Pricing Analysis

Price comparison per million tokens

Step-3.5-Flash costs less

For input processing, DeepSeek-V4-Pro-0813 ($0.43/1M tokens) is 4.3x more expensive than Step-3.5-Flash ($0.10/1M tokens).

For output processing, DeepSeek-V4-Pro-0813 ($0.87/1M tokens) is 2.2x more expensive than Step-3.5-Flash ($0.40/1M tokens).

In conclusion, DeepSeek-V4-Pro-0813 is more expensive than Step-3.5-Flash.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Tue Aug 25 2026 • llm-stats.com
DeepSeek
DeepSeek-V4-Pro-0813
Input tokens$0.43
Output tokens$0.87
Best providerDeepSeek
StepFun
Step-3.5-Flash
Input tokens$0.10
Output tokens$0.40
Best providerStepFun
Notice missing or incorrect data?Start an Issue→

Model Size

Parameter count comparison

1404.0B diff

DeepSeek-V4-Pro-0813 has 1404.0B more parameters than Step-3.5-Flash, making it 716.3% larger.

DeepSeek
DeepSeek-V4-Pro-0813
1.6Tparameters
StepFun
Step-3.5-Flash
196.0Bparameters
1600.0B
DeepSeek-V4-Pro-0813
196.0B
Step-3.5-Flash

Context Window

Maximum input and output token capacity

DeepSeek-V4-Pro-0813 accepts 1,048,576 input tokens compared to Step-3.5-Flash's 65,536 tokens. DeepSeek-V4-Pro-0813 can generate longer responses up to 393,216 tokens, while Step-3.5-Flash is limited to 8,192 tokens.

DeepSeek
DeepSeek-V4-Pro-0813
Input1,048,576 tokens
Output393,216 tokens
StepFun
Step-3.5-Flash
Input65,536 tokens
Output8,192 tokens
Tue Aug 25 2026 • llm-stats.com

License

Usage and distribution terms

DeepSeek-V4-Pro-0813 is licensed under MIT, while Step-3.5-Flash uses Apache 2.0.

License differences may affect how you can use these models in commercial or open-source projects.

DeepSeek-V4-Pro-0813

MIT

Open weights

Step-3.5-Flash

Apache 2.0

Open weights

Release Timeline

When each model was launched

DeepSeek-V4-Pro-0813 was released on 2026-08-13, while Step-3.5-Flash was released on 2026-02-02.

DeepSeek-V4-Pro-0813 is 6 months newer than Step-3.5-Flash.

DeepSeek-V4-Pro-0813

Aug 13, 2026

1 weeks ago

6mo newer
Step-3.5-Flash

Feb 2, 2026

6 months ago

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

DeepSeek-V4-Pro-0813 is available from DeepSeek, DeepInfra, Novita, Together. Step-3.5-Flash is available from StepFun.

DeepSeek-V4-Pro-0813

deepseek logo
DeepSeek
Input Price:Input: $0.43/1MOutput Price:Output: $0.87/1M
deepinfra logo
Deepinfra
Input Price:Input: $1.30/1MOutput Price:Output: $2.60/1M
novita logo
Novita
Input Price:Input: $1.32/1MOutput Price:Output: $3.96/1M
together logo
Together
Input Price:Input: $1.32/1MOutput Price:Output: $3.96/1M

Step-3.5-Flash

stepfun logo
StepFun
Input Price:Input: $0.10/1MOutput Price:Output: $0.40/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against DeepSeek-V4-Pro-0813 and Step-3.5-Flash side-by-side, then vote on the output you prefer.

DeepSeek-V4-Pro-0813
✓ Preferred
Step-3.5-Flash
Open in Playground

FAQ

Common questions about DeepSeek-V4-Pro-0813 vs Step-3.5-Flash.

Which is better, DeepSeek-V4-Pro-0813 or Step-3.5-Flash?

DeepSeek-V4-Pro-0813 (DeepSeek) and Step-3.5-Flash (StepFun) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does DeepSeek-V4-Pro-0813 compare to Step-3.5-Flash in benchmarks?

DeepSeek-V4-Pro-0813 scores Terminal-Bench 2.1: 87.9%, CyberGym: 83.3%, Toolathlon: 74.1%, DSBench-FullStack: 71.1%, DSBench-Hard: 67.2%. Step-3.5-Flash scores AIME 2025: 97.3%, Tau-bench: 88.2%, LiveCodeBench v6: 86.4%, IMO-AnswerBench: 85.4%, SWE-Bench Verified: 74.4%.

Is DeepSeek-V4-Pro-0813 cheaper than Step-3.5-Flash?

Step-3.5-Flash is 4.3x cheaper for input tokens. DeepSeek-V4-Pro-0813 costs $0.43/M input and $0.87/M output via deepseek. Step-3.5-Flash costs $0.10/M input and $0.40/M output via stepfun.

What are the context window sizes for DeepSeek-V4-Pro-0813 and Step-3.5-Flash?

DeepSeek-V4-Pro-0813 supports 1.0M tokens and Step-3.5-Flash supports 66K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between DeepSeek-V4-Pro-0813 and Step-3.5-Flash?

Key differences include context window (1.0M vs 66K), input pricing ($0.43 vs $0.10/M), licensing (MIT vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes DeepSeek-V4-Pro-0813 and Step-3.5-Flash?

DeepSeek-V4-Pro-0813 is developed by DeepSeek and Step-3.5-Flash is developed by StepFun.

Related comparisons