Gemini 3.5 Flash vs Doubao Seed 2.1 Turbo
Gemini 3.5 Flash wins on Overall, Coding, Multimodal. Every numeric field is compared below, with a worked monthly-cost example and a pick rule for each use case.
Verdict at a glance
Choose Gemini 3.5 Flash if you…
- Extremely fast
- Low price
- Native multimodal
- Built for scale
- Best for: Fast tasks, Multimodal, Low cost
Choose Doubao Seed 2.1 Turbo if you…
- Low price
- Video support
- Fast
- Built for volume
- Best for: Volume production, Video, Low cost
Head-to-head aggregate scores
Scores are 0–100, aggregated from public benchmark information and independently weighted across three leaderboards. Rank is out of 22 tracked models.
Aggregated from public sources and independently weighted; methodology on the Terms page. Scores within 3 points are treated as statistically tied.
Specs & pricing — every field side by side
List API prices in USD per 1M tokens. The highlighted cell is the stronger value/capability on that row.
| Dimension | Gemini 3.5 Flash | Doubao Seed 2.1 Turbo | Verdict |
|---|---|---|---|
| Vendor | Google (US) | ByteDance (CN) | Different vendors |
| Released | 2026.07 | 2026.06 | Gemini 3.5 Flash is newer |
| Overall (rank) | 69 · #14 | 63 · #20 | Gemini 3.5 Flash +6 |
| Coding | 64 · #17 | 61 · #19 | Gemini 3.5 Flash +3 |
| Multimodal | 86 · #7 | 73 · #17 | Gemini 3.5 Flash +13 |
| Context window | 1M | 256K | Gemini 3.5 Flash larger |
| Max output | 128K | 256K | Doubao Seed 2.1 Turbo longer |
| Effective-context | 88 | 90 | Doubao Seed 2.1 Turbo more reliable |
| Input $/1M | $1.5 | $0.42 | Doubao Seed 2.1 Turbo cheaper |
| Output $/1M | $9 | $2.08 | Doubao Seed 2.1 Turbo cheaper |
| Cache discount | none | custom | Doubao Seed 2.1 Turbo deeper |
| Speed | ~80 tok/s | ~75 tok/s | Gemini 3.5 Flash faster |
| TTFT | 0.3s | 0.4s | Gemini 3.5 Flash snappier |
| Function calling | 75 | 80 | Doubao Seed 2.1 Turbo ahead |
| Refusal rate | ~10% | ~10% | Tie |
| English | 85 | 68 | Gemini 3.5 Flash |
| Chinese | 72 | 90 | Doubao Seed 2.1 Turbo |
| Modalities | text, image, audio, video | text, image, video | different coverage |
| Open weights | No | No | Both closed |
| Fine-tuning | Yes | Yes | |
| Free tier | Gemini App free; API free tier | Doubao App free | |
| SOC2 / no-train | yes / yes | no / yes | |
| Private deployment | No | Yes | Doubao Seed 2.1 Turbo |
Fields drawn from vendor public documentation and the Modelspectra 22-model dataset; speed varies with network, concurrency and prompt length. Verify current pricing before purchase.
Dimension-by-dimension analysis
Reasoning & overall intelligence
Gemini 3.5 Flash leads the overall aggregate by 6 points (69 vs 63). That is a meaningful, not marginal, edge on hard, multi-step reasoning, while Doubao Seed 2.1 Turbo remains a strong generalist that is not out of its depth on routine work.
Agentic coding
This is a modest gap: Gemini 3.5 Flash scores 64 against 61. On multi-file edits, SWE-style tickets and long-horizon agent loops Gemini 3.5 Flash needs fewer correction turns; Doubao Seed 2.1 Turbo is still competent for scripts and assisted completion but trails as task complexity rises.
Multimodal
Gemini 3.5 Flash leads multimodal 86 vs 73. A concrete modality difference: Gemini 3.5 Flash additionally handles audio. Both accept video, so weigh their video-understanding reliability, not mere support.
Speed & latency
Gemini 3.5 Flash is faster in interactive use: ~80 tok/s with 0.3s TTFT versus ~75 tok/s with 0.4s TTFT (about 1.1× the throughput). For conversational UIs where perceived responsiveness drives retention, that edge is a real product factor even when raw reasoning is lower.
Context: window vs usable recall
Nominal windows are 1M for Gemini 3.5 Flash and 256K for Doubao Seed 2.1 Turbo. Crucially, the larger nominal window does not win on usable recall: Gemini 3.5 Flash advertises 1M but Doubao Seed 2.1 Turbo scores higher on effective-context (90 vs 88), i.e. it actually retains more of what it was given.
Price & total cost
Doubao Seed 2.1 Turbo is the cheaper API at $0.42/$2.08 versus Gemini 3.5 Flash at $1.5/$9 per 1M input/output tokens — list input is about 3.6× lower.
Chinese vs English
English: Gemini 3.5 Flash 85 vs Doubao Seed 2.1 Turbo 68. Chinese: 72 vs 90. For Chinese-language production, Doubao Seed 2.1 Turbo is the stronger pick. Note that non-Chinese models generally require overseas network access for their APIs.
Tool use & ecosystem
Function-calling score: Gemini 3.5 Flash 75 vs Doubao Seed 2.1 Turbo 80, so Doubao Seed 2.1 Turbo has the edge on structured tool use. Fine-tuning is available from Gemini 3.5 Flash and Doubao Seed 2.1 Turbo. Factor in existing SDK/plugin familiarity — switching cost often outweighs a few-point tool-use gap.
Cost worked example — same workload, real token math
Assume a production workload of 100M input + 30M output tokens per month, with 90% of input tokens served from cache. Figures use public list prices.
| Scenario · per month | Gemini 3.5 Flash | Doubao Seed 2.1 Turbo | Gap |
|---|---|---|---|
| List priceno cache applied | $420100M in × $1.5 + 30M out × $9 | $104100M in × $0.42 + 30M out × $2.08 | 4.04×gap |
| With caching90% of inputs cache-hit | $420no published cache discount | $104no published cache discount | 4.04×gap |
Illustrative model; your input/output mix and cache-hit ratio change the result. Prices are list rates before any enterprise agreement.