DeepSeek V3.1 vs GPT-5.5 Instant
DeepSeek V3.1 (2025) and GPT-5.5 Instant (2026) are compact production models from DeepSeek and OpenAI. DeepSeek V3.1 ships a 64k-token context window, while GPT-5.5 Instant ships a 400k-token context window. On pricing, DeepSeek V3.1 costs $0.27/1M input tokens versus $5/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
DeepSeek V3.1 is ~1752% cheaper at $0.27/1M; pay for GPT-5.5 Instant only for coding workflow support.
Decision scorecard
Local evidence first| Signal | DeepSeek V3.1 | GPT-5.5 Instant |
|---|---|---|
| Best for | multimodal apps and provider-routed production | multimodal apps and tool-calling agents |
| Decision fit | Coding, Agents, and Vision | Coding, RAG, and Agents |
| Context window | 64k | 400k |
| Cheapest output | $1/1M tokens | $30/1M tokens |
| Provider routes | 9 tracked | 1 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- DeepSeek V3.1 has the lower cheapest tracked output price at $1/1M tokens.
- DeepSeek V3.1 has broader tracked provider coverage for fallback and route flexibility.
- Local decision data tags DeepSeek V3.1 for Coding, Agents, and Vision.
- GPT-5.5 Instant has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.5 Instant uniquely exposes JSON / Tool use in local model data.
- Local decision data tags GPT-5.5 Instant for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
DeepSeek V3.1
$466
Cheapest tracked route/tier: Novita AI
GPT-5.5 Instant
$11,500
Cheapest tracked route/tier: OpenAI API
Estimated monthly gap: $11,034. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for DeepSeek V3.1 and GPT-5.5 Instant; plan for SDK, billing, or endpoint changes.
- GPT-5.5 Instant is $29/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- GPT-5.5 Instant adds JSON / Tool use in local capability data.
- No overlapping tracked provider route is sourced for GPT-5.5 Instant and DeepSeek V3.1; plan for SDK, billing, or endpoint changes.
- DeepSeek V3.1 is $29/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for JSON / Tool use before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-08-21 | 2026-05-05 |
| Context window | 64k | 400k |
| Parameters | 671B total, 37B active (MoE) | — |
| Architecture | Mixture of Experts | Decoder Only |
| License | MITOSI-approved | Proprietary |
| Openness | Open source | Proprietary |
| Weights | Unknown | Not released |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: permitted | Commercial use: conditional |
| Knowledge cutoff | - | 2025-08 |
Pricing and availability
| Pricing attribute | DeepSeek V3.1 | GPT-5.5 Instant |
|---|---|---|
| Input price | $0.27/1M tokens | $5/1M tokens |
| Output price | $1/1M tokens | $30/1M tokens |
| Providers |
Capabilities
| Capability | DeepSeek V3.1 | GPT-5.5 Instant |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | No | No |
| JSON / Tool use | No | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
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Last reviewed: 2026-09-24. Data sourced from public model cards and provider documentation.