OpenAI compatible API · Attested · Public status

DeepSeek: DeepSeek V4 Pro 0423 vs Step 3.5 Flash 2603

DeepSeek V4 Pro 0423 has more Credits provider routes, the larger context window and the lower measured p50 time to first token. Step 3.5 Flash 2603 has the lower published input-plus-output rate. Compare price, speed, context, and privacy.

Verify gateway

Onebase URL to migrate

100sof models and routes

0prompt or output logs. Always.

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 Pro 0423 has more Credits provider routes, the larger context window and the lower measured p50 time to first token. Step 3.5 Flash 2603 has the lower published input-plus-output rate.

$0.79125/1MDeepSeek: DeepSeek V4 Pro 0423 cheapest route

$0.422/1MStep 3.5 Flash 2603 cheapest route

1253 msDeepSeek: DeepSeek V4 Pro 0423 fastest measured p50 TTFT via deepseek

2307 msStep 3.5 Flash 2603 fastest measured p50 TTFT via stepfun

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 Pro 0423Step 3.5 Flash 2603

Model iddeepseek/deepseek-v4-prostepfun/step-3.5-flash-2603

Publisher DeepSeek StepFun

AI IQ IQ 124#29 —

Context1,048,576 tokens262,144 tokens

Credits provider routes161

Cheapest route$0.79125/1M$0.422/1M

Cached input$0.01/1M to $0.739555/1M$0.0211/1M

Privacy posturehas ZDR routeprovider posture varies

Fastest measured p50 TTFT1253 ms via deepseek2307 ms via stepfun

Highest measured throughputnot enough datanot enough data

Recent route uptime range66.67% to 100.00%100.00%

Modes chat chat

DeepSeek: DeepSeek V4 Pro 0423 routes

Overview16 Credits routes
PricingInput, cached input, and output rates
BenchmarksTrustedRouter and external sources
ProvidersAll serving providers

Step 3.5 Flash 2603 routes

Overview1 Credits routes

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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-pro",
    messages=messages,
)

Questions

Which should I use, DeepSeek: DeepSeek V4 Pro 0423 or Step 3.5 Flash 2603?

DeepSeek V4 Pro 0423 has more Credits provider routes, the larger context window and the lower measured p50 time to first token. Step 3.5 Flash 2603 has the lower published input-plus-output rate.

Is DeepSeek: DeepSeek V4 Pro 0423 or Step 3.5 Flash 2603 cheaper?

The current cheapest TrustedRouter route is $0.79125/1M for DeepSeek: DeepSeek V4 Pro 0423 and $0.422/1M for Step 3.5 Flash 2603. The comparison uses current catalog prices and updates as provider pricing changes.

Is DeepSeek: DeepSeek V4 Pro 0423 or Step 3.5 Flash 2603 faster?

Current measured p50 time to first token is 1253 ms for DeepSeek: DeepSeek V4 Pro 0423 and 2307 ms for Step 3.5 Flash 2603. These are routed probe measurements, not vendor-advertised speeds, and update as new samples arrive.

Can I test DeepSeek: DeepSeek V4 Pro 0423 and Step 3.5 Flash 2603 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-pro and stepfun/step-3.5-flash-2603. This makes side-by-side evals possible without maintaining two provider integrations.