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DeepSeek: DeepSeek V4.1 Flash vs stepfun-ai/Step-5-Preview

Try both on us. Starter credit covers your first requests, then one key routes DeepSeek V4.1 Flash and stepfun-ai/Step-5-Preview. Switch by changing the model name.

Compare routesProviders, price, context, and policy posture in one view.

Use auto when uptime mattersKeep a primary model and let fallback handle provider failures.

Same API shapeUse the OpenAI client and set the model you want.

Practical read

Monthly evidence

DeepSeek V4.1 Flash has the lower published input-plus-output rate, more Credits provider routes and the lower measured p50 time to first token. Their context windows are the same size.

$0.15825/1MDeepSeek: DeepSeek V4.1 Flash cheapest route

$3.9035/1Mstepfun-ai/Step-5-Preview cheapest route

886 msDeepSeek: DeepSeek V4.1 Flash fastest measured p50 TTFT via baseten

2239 msstepfun-ai/Step-5-Preview fastest measured p50 TTFT via nvidia-nim

The price comparison adds each route's rate for one million input tokens and one million output tokens; your cost depends on your input/output mix. Prices and live route measurements can change. Use the monthly reports when you need a stable evidence window, then run a small task-specific eval before choosing a production default.

DeepSeek: DeepSeek V4.1 Flashstepfun-ai/Step-5-Preview

Model iddeepseek/deepseek-v4.1-flashstepfun-ai/step-5-preview

Publisher DeepSeek StepFun

AI IQ IQ 126#24 —

Context1,048,576 tokens1,048,576 tokens

Credits provider routes243

Cheapest route$0.15825/1M$3.9035/1M

Cached input$0.01/1M to $0.1899/1M$0.05275/1M

Privacy posturehas Confidential route (E2EE + ZDR)has ZDR route

Fastest measured p50 TTFT886 ms via baseten2239 ms via nvidia-nim

Highest measured throughputnot enough datanot enough data

Recent route uptime range96.67% to 100.00%33.33% to 100.00%

Modes chat decide chat

DeepSeek: DeepSeek V4.1 Flash routes

Overview24 Credits routes
PricingInput, cached input, and output rates
ProvidersAll serving providers

stepfun-ai/Step-5-Preview routes

Overview3 Credits routes
PricingInput, cached input, and output rates
ProvidersAll serving providers

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Production choice

Pick a default model. Keep fallback enabled.

TrustedRouter is useful when you know the model you want, but still need provider rollover, budget limits, usage records, and a prompt path you can verify.

OpenAI clientPython

client = OpenAI(
    base_url="https://api.trustedrouter.com/v1",
    api_key="sk-tr-v1-..."
)

response = client.chat.completions.create(
    model="deepseek/deepseek-v4.1-flash",
    messages=messages,
)

Questions

Which should I use, DeepSeek: DeepSeek V4.1 Flash or stepfun-ai/Step-5-Preview?

DeepSeek V4.1 Flash has the lower published input-plus-output rate, more Credits provider routes and the lower measured p50 time to first token. Their context windows are the same size.

Is DeepSeek: DeepSeek V4.1 Flash or stepfun-ai/Step-5-Preview cheaper?

The current cheapest TrustedRouter route is $0.15825/1M for DeepSeek: DeepSeek V4.1 Flash and $3.9035/1M for stepfun-ai/Step-5-Preview. The comparison uses current catalog prices and updates as provider pricing changes.

Is DeepSeek: DeepSeek V4.1 Flash or stepfun-ai/Step-5-Preview faster?

Current measured p50 time to first token is 886 ms for DeepSeek: DeepSeek V4.1 Flash and 2239 ms for stepfun-ai/Step-5-Preview. These are routed probe measurements, not vendor-advertised speeds, and update as new samples arrive.

Can I test DeepSeek: DeepSeek V4.1 Flash and stepfun-ai/Step-5-Preview with the same API?

Yes. Use the same OpenAI-compatible TrustedRouter base URL and API key, then change only the model id between deepseek/deepseek-v4.1-flash and stepfun-ai/step-5-preview. This makes side-by-side evals possible without maintaining two provider integrations.