GPT-5.5 vs Doubao Seed Evolving
GPT-5.5 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 GPT-5.5 if you…
- Balanced with no weak spot
- Richest ecosystem
- Mature plugin/function calling
- Strong creative writing
- Best for: General tasks, Creative writing, Coding
Choose Doubao Seed Evolving if you…
- Continuously updated
- 1M context
- Good Chinese
- ByteDance ecosystem
- Best for: Chinese, Long context, Continuously evolving
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 | GPT-5.5 | Doubao Seed Evolving | Verdict |
|---|---|---|---|
| Vendor | OpenAI (US) | ByteDance (CN) | Different vendors |
| Released | 2026.04 | 2026.07 | Doubao Seed Evolving is newer |
| Overall (rank) | 81 · #5 | 68 · #15 | GPT-5.5 +13 |
| Coding | 75 · #8 | 67 · #14 | GPT-5.5 +8 |
| Multimodal | 85 · #8 | 83 · #9 | GPT-5.5 +2 |
| Context window | 1.05M | 1M | GPT-5.5 larger |
| Max output | 128K | 256K | Doubao Seed Evolving longer |
| Effective-context | 90 | 92 | Doubao Seed Evolving more reliable |
| Input $/1M | $5 | $0.83 | Doubao Seed Evolving cheaper |
| Output $/1M | $30 | $4.17 | Doubao Seed Evolving cheaper |
| Cache discount | 50% off | custom | GPT-5.5 deeper |
| Speed | ~50 tok/s | ~60 tok/s | Doubao Seed Evolving faster |
| TTFT | 0.8s | 0.5s | Doubao Seed Evolving snappier |
| Function calling | 95 | 82 | GPT-5.5 ahead |
| Refusal rate | ~15% | ~10% | Doubao Seed Evolving less restrictive |
| English | 94 | 70 | GPT-5.5 |
| Chinese | 76 | 93 | Doubao Seed Evolving |
| Modalities | text, image | text, image | Same |
| Open weights | No | No | Both closed |
| Fine-tuning | Yes | No | |
| Free tier | ChatGPT free tier available (rate-limited); Plus $20/month | Doubao App free | |
| SOC2 / no-train | yes / yes | no / yes | |
| Private deployment | No | Yes | Doubao Seed Evolving |
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
GPT-5.5 leads the overall aggregate by 13 points (81 vs 68). That is a meaningful, not marginal, edge on hard, multi-step reasoning, while Doubao Seed Evolving remains a strong generalist that is not out of its depth on routine work.
Agentic coding
This is a modest gap: GPT-5.5 scores 75 against 67. On multi-file edits, SWE-style tickets and long-horizon agent loops GPT-5.5 needs fewer correction turns; Doubao Seed Evolving is still competent for scripts and assisted completion but trails as task complexity rises.
Multimodal
GPT-5.5 leads multimodal 85 vs 83. Neither emits native video, so the comparison is about parsing images and documents, not generation.
Speed & latency
Doubao Seed Evolving is faster in interactive use: ~60 tok/s with 0.5s TTFT versus ~50 tok/s with 0.8s TTFT (about 1.2× 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 1.05M for GPT-5.5 and 1M for Doubao Seed Evolving. Crucially, the larger nominal window does not win on usable recall: GPT-5.5 advertises 1.05M but Doubao Seed Evolving scores higher on effective-context (92 vs 90), i.e. it actually retains more of what it was given.
Price & total cost
Doubao Seed Evolving is the cheaper API at $0.83/$4.17 versus GPT-5.5 at $5/$30 per 1M input/output tokens — list input is about 6.0× lower. Cache discounts (GPT-5.5 50%) shift the effective bill, worked out below.
Chinese vs English
English: GPT-5.5 94 vs Doubao Seed Evolving 70. Chinese: 76 vs 93. For Chinese-language production, Doubao Seed Evolving is the stronger pick. Note that non-Chinese models generally require overseas network access for their APIs.
Tool use & ecosystem
Function-calling score: GPT-5.5 95 vs Doubao Seed Evolving 82, so GPT-5.5 has the edge on structured tool use. Fine-tuning is available from GPT-5.5. 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 | GPT-5.5 | Doubao Seed Evolving | Gap |
|---|---|---|---|
| List priceno cache applied | $1,400100M in × $5 + 30M out × $30 | $208100M in × $0.83 + 30M out × $4.17 | 6.73×gap |
| With caching90% of inputs cache-hit | $1,17590M cached in × $2.5 + 10M in × $5 + 30M out × $30 | $208no published cache discount | 5.65×gap |
Illustrative model; your input/output mix and cache-hit ratio change the result. Prices are list rates before any enterprise agreement.