SStepFun: Step 3.5 Flash
stepfun/step-3-5-flashStep 3.5 Flash is StepFun's most capable open-source foundation model.
Modalities
In / out per 1M$0.10 / $0.30
Context256K
ReleasedJan 29, 2026
Providers
1 provider serves this model upstream.
| Provider | Input /M | Output /M | Cache read /M | Latency P50 | Throughput P50 | Uptime |
|---|---|---|---|---|---|---|
 SiliconFlowfp8 | $0.10 | $0.30 | Variable | 1.51s | 61 tps | 99.13% |
Market-wide measurements, refreshed every 15 minutes. They describe who serves Step 3.5 Flash in general, not how ProjectCOZY routes your requests.
Pricing
List rates per 1M tokens — what Step 3.5 Flash costs pay-as-you-go elsewhere, not what you pay here.
Input
$0.10
per 1M tokens
Output
$0.30
per 1M tokens
Cache read
—
not published
Included in every pass
Step 3.5 Flash is included in every ProjectCOZY pass at no extra cost — one flat rate, no per-token metering. The rates above are there for comparison.
Performance
Time to first token and output speed across every provider, over the last 3 days.
0.0s50.0s100.0s150.0s200.0s
Oct 16, 12 AMOct 16, 8 AMOct 16, 4 PMOct 17, 12 AMOct 17, 8 AMOct 17, 4 PMOct 18, 12 AMOct 18, 8 AMOct 18, 4 PMOct 19, 12 AMOct 19, 8 AM
Median 90th percentile 99th percentile
0 tok/s50 tok/s100 tok/s150 tok/s200 tok/s
Oct 16, 12 AMOct 16, 8 AMOct 16, 4 PMOct 17, 12 AMOct 17, 8 AMOct 17, 4 PMOct 18, 12 AMOct 18, 8 AMOct 18, 4 PMOct 19, 12 AMOct 19, 8 AM
Median 90th percentile 99th percentile
Uptime
100% of requests were served successfully over the last 3 days, across all providers.
Last 3 daysAvailability 98.7%
Oct 16, 10:00 AMNow
Availability over the last 24 hoursAvailability 98.96%
100% 75% 50% 25%
Oct 18, 10:20 AMNow
Apps
Tools that most often run Step 3.5 Flash, by tokens this week.
Activity
8.2B tokens processed market-wide in the last month.
0200.0M400.0M600.0M800.0M
Sep 19Sep 24Sep 29Oct 4Oct 9Oct 14Oct 19
Tokens
FAQ
Which model id do I use for Step 3.5 Flash?
stepfun/step-3.5-flash. Send it as the model field from any OpenAI-compatible client, against http://192.168.1.55/v1.
How much context does Step 3.5 Flash hold?
262,144 tokens per request, of which up to 65,536 can be the response.
What can it accept and return?
Input: text. Output: text.
What does Step 3.5 Flash cost on a pass?
Nothing beyond the pass itself. Pay-as-you-go elsewhere it lists at $0.10 per 1M input tokens and $0.30 per 1M output tokens.
Who built Step 3.5 Flash?
StepFun, in the Step family.
Explore
Other models your pass can call.
