Seed 2.1 Pro vs GPT-5.5 Pro
Benchmark Performance
Available Benchmarks
Technical Differences
Side-by-Side Facts
| Field | Seed 2.1 Pro | GPT-5.5 Pro |
|---|---|---|
| Developer | ByteDance Seed | OpenAI |
| Family | Seed 2 1 | Gpt 5 5 |
| Model | Seed 2.1 Pro | GPT-5.5 Pro |
| Version | Seed 2.1 Pro | GPT-5.5 Pro |
| Lifecycle | active | active |
| Released | 2026-06-23 | 2026-04-23 |
| Knowledge cutoff | Unknown | 2025-12-01 |
| Input modalities | Text, Image, Video | Text, Image |
| Output modalities | Text | Text |
| Context window | Unknown | 1,050K |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Unknown | Openai (Standard), Openrouter (Standard) |
| Capabilities | agents, chat, computer-use, generation, reasoning, structured_outputs, tools | chat, generation, reasoning, structured_outputs, tools |
12 comparable fields · 7 material differences · Pair passes the primary-source comparison gate
Seed 2.1 Pro Capabilities
GPT-5.5 Pro Capabilities
Internal Comparison Graph
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|---|---|---|---|
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Seed 2.1 ProByteDance Seed | vs | cross-developer peersimage, text |
Primary Evidence
Sources and Freshness
Questions
Seed 2.1 Pro vs GPT-5.5 Pro FAQs
Is Seed 2.1 Pro or GPT-5.5 Pro better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Seed 2.1 Pro and GPT-5.5 Pro, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Seed 2.1 Pro or GPT-5.5 Pro?+
Only GPT-5.5 Pro has a directly sourced input price: $30.00 per million tokens. Only GPT-5.5 Pro has a directly sourced output price: $180.00 per million tokens.
Which has a larger context window, Seed 2.1 Pro or GPT-5.5 Pro?+
Neither model has a larger sourced context window in this comparison. Seed 2.1 Pro is — and GPT-5.5 Pro is 1,050K.
Which performs better in benchmarks, Seed 2.1 Pro or GPT-5.5 Pro?+
There is no overall benchmark winner: At least two independently verified, protocol-matched benchmarks are required for an overall winner.
Can Seed 2.1 Pro or GPT-5.5 Pro be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Seed 2.1 Pro is not marked open weight; GPT-5.5 Pro is not marked open weight.
Can Seed 2.1 Pro and GPT-5.5 Pro understand images?+
Seed 2.1 Pro is documented with image input; GPT-5.5 Pro is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Seed 2.1 Pro or GPT-5.5 Pro?+
Neither has a larger sourced maximum output. Seed 2.1 Pro is — and GPT-5.5 Pro is 128K.
Do Seed 2.1 Pro and GPT-5.5 Pro support reasoning and tool use?+
Seed 2.1 Pro: reasoning, tool calling, and image input. GPT-5.5 Pro: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Seed 2.1 Pro or GPT-5.5 Pro?+
Seed 2.1 Pro has 0 sourced provider routes; GPT-5.5 Pro has 2, so GPT-5.5 Pro has broader tracked availability.
Which offers better value, Seed 2.1 Pro or GPT-5.5 Pro?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.