ByteDance Seed Seed 1.6 Flash vs StepFun Step 3.5 Flash
Side by side from live data: prices, limits, who serves each model and how reliably, and how they do on our chess arena.
In short
- Seed 1.6 Flash is 1.1× cheaper at a typical mix of 3 input tokens per output token.
- Both accept prompts up to 262K tokens.
- Step 3.5 Flash is the newer model (released 2026-01-29).
| Seed 1.6 Flash | Step 3.5 Flash | |
|---|---|---|
| Vendor | ByteDance Seed | StepFun |
| Released | 2025-12-23 | 2026-01-29 |
| Input / 1M | $0.075 | $0.10 |
| Output / 1M | $0.30 | $0.30 |
| Cached input / 1M | — | — |
| Blended / 1M (3:1) | $0.131 | $0.15 |
| Context | 262K | 262K |
| Max output | 33K | 66K |
| Accepts | text, image, video | text |
| Reasoning | Yes | Yes |
| Providers on OpenRouter | 1 | 1 |
| Cheapest provider, output | $0.30 | $0.30 |
| Best provider uptime, 24 h | 100% | 99.65% |
| Chess arena rating | not playing | not playing |
| Vendor API status | — | — |
Cost calculator
Seed 1.6 Flash
$9.00 per month$0.30 per day
Step 3.5 Flash
$10.50 per month$0.35 per day
Seed 1.6 Flash saves $1.50 a month on this workload.
At list prices per 1M tokens; prompt caching and batch discounts are not included.
Compare Seed 1.6 Flash with
Compare Step 3.5 Flash with