Qwen3.8 27B vs stepfun-ai/Step-3.5-Flash

Practical read: stepfun-ai/Step-3.5-Flash reads four times more context. One API key runs both.

No card required. Start with 1 million free tokens.

Side by side:

Qwen: Qwen3.8 27B compared with stepfun-ai/Step-3.5-Flash
Attribute	Qwen3.8 27B `qwen/qwen3.8-27b`	stepfun-ai/Step-3.5-Flash `stepfun-ai/step-3.5-flash`
Price, 1M in + out	$0.39 Engy, cheapest route	$0.42 Featherless AI, cheapest route
Best for		Long documents
Input / output, 1M	$0.047 / $0.34	$0.11 / $0.32
Cached input	$0.01/1M to $0.180405/1M	Not published
Context window	66K 65,536 tokens	262K 262,144 tokens
First token, p50	0.93 s via Crusoe	Measuring
AI IQ	IQ 115 #57 on AI IQ	Unrated
Provider routes	21 with failover	1
Privacy	Confidential E2EE and zero retention route	Zero retention route
Recent route uptime range	100.00%	not enough data
Publisher	Alibaba Cloud Model Studio	StepFun
Modes	chat	chat
More detail	Overview Pricing Providers	Overview

Price adds one million input and one million output tokens on the cheapest route. Prices and speed change: see the monthly reports and run a small eval before you choose a default.

Test both with your agent

Paste this into Claude Code, Cursor or any coding agent.

Compare Qwen3.8 27B and stepfun-ai/Step-3.5-Flash in this project through TrustedRouter.

1. Read https://trustedrouter.com/docs/llms.txt
2. Point the OpenAI-compatible client at
   https://api.trustedrouter.com/v1 and read the key from
   TRUSTEDROUTER_API_KEY.
3. Run our eval prompts on qwen/qwen3.8-27b, then on stepfun-ai/step-3.5-flash.
4. Show me cost, latency and quality side by side before changing the default.

import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.trustedrouter.com/v1",
    api_key=os.environ["TRUSTEDROUTER_API_KEY"],
)
for model in ("qwen/qwen3.8-27b", "stepfun-ai/step-3.5-flash"):
    response = client.chat.completions.create(
        model=model,
        messages=[{"role": "user", "content": "What is the capital of France?"}],
    )
    print(model, response.choices[0].message.content)

for model in qwen/qwen3.8-27b stepfun-ai/step-3.5-flash; do
  curl https://api.trustedrouter.com/v1/chat/completions \
    -H "Authorization: Bearer $TRUSTEDROUTER_API_KEY" \
    -H "Content-Type: application/json" \
    -d "{\"model\": \"$model\", \"messages\": [{\"role\": \"user\", \"content\": \"What is the capital of France?\"}]}"
done

Your agent will need an API key.

Questions

Which should I use, Qwen: Qwen3.8 27B or stepfun-ai/Step-3.5-Flash?

Qwen: Qwen3.8 27B has the lower published input-plus-output rate and more Credits provider routes. stepfun-ai/Step-3.5-Flash has the larger context window. There is not enough recent probe data to compare speed.

Is Qwen: Qwen3.8 27B or stepfun-ai/Step-3.5-Flash cheaper?

The current cheapest TrustedRouter route is $0.385075/1M for Qwen: Qwen3.8 27B and $0.422/1M for stepfun-ai/Step-3.5-Flash. The comparison uses current catalog prices and updates as provider pricing changes.

Is Qwen: Qwen3.8 27B or stepfun-ai/Step-3.5-Flash faster?

Current measured p50 time to first token is 929 ms for Qwen: Qwen3.8 27B and not enough data for stepfun-ai/Step-3.5-Flash. These are routed probe measurements, not vendor-advertised speeds, and update as new samples arrive.

Can I test Qwen: Qwen3.8 27B and stepfun-ai/Step-3.5-Flash with the same API?

Yes. Use the same OpenAI-compatible TrustedRouter base URL and API key, then change only the model id between qwen/qwen3.8-27b and stepfun-ai/step-3.5-flash. This makes side-by-side evals possible without maintaining two provider integrations.

More comparisons

All comparisons

Try Qwen3.8 27B and stepfun-ai/Step-3.5-Flash with one key.

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.

No card required. Start with 1 million free tokens.