GPT-5.5 vs Muse Spark
GPT-5.5 (2026) and Muse Spark (2026) are frontier-tier reasoning models from OpenAI and AI at Meta. GPT-5.5 ships a 1.1M-token context window, while Muse Spark ships a not-yet-sourced context window. On SWE-bench Verified, GPT-5.5 leads by 11.3 pts. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
GPT-5.5 is safer overall; choose Muse Spark when vision-heavy evaluation matters.
Decision scorecard
Local evidence first| Signal | GPT-5.5 | Muse Spark |
|---|---|---|
| Decision fit | Coding, RAG, and Agents | Coding, Agents, and Vision |
| Context window | 1.1M | — |
| Cheapest output | $30/1M tokens | - |
| Provider routes | 2 tracked | 0 tracked |
| Shared benchmarks | SWE-bench Verified leader | 3 rows |
Decision tradeoffs
- GPT-5.5 leads the largest shared benchmark signal on SWE-bench Verified by 11.3 points.
- GPT-5.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.5 has broader tracked provider coverage for fallback and procurement flexibility.
- GPT-5.5 uniquely exposes Structured outputs and Code execution in local model data.
- Local decision data tags GPT-5.5 for Coding, RAG, and Agents.
- Muse Spark leads the largest shared benchmark signal on Chatbot Arena by 3 points.
- Local decision data tags Muse Spark for Coding, Agents, and Vision.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
GPT-5.5
$11,500
Cheapest tracked route: OpenAI API
Muse Spark
Unavailable
No complete token price in local provider data
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for GPT-5.5 and Muse Spark; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Structured outputs and Code execution before moving production traffic.
- No overlapping tracked provider route is sourced for Muse Spark and GPT-5.5; plan for SDK, billing, or endpoint changes.
- GPT-5.5 adds Structured outputs and Code execution in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-23 | 2026-04-08 |
| Context window | 1.1M | — |
| Parameters | — | — |
| Architecture | decoder only | decoder-only-transformer |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-12 | - |
Pricing and availability
| Pricing attribute | GPT-5.5 | Muse Spark |
|---|---|---|
| Input price | $5/1M tokens | - |
| Output price | $30/1M tokens | - |
| Providers | - |
Capabilities
| Capability | GPT-5.5 | Muse Spark |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | No |
| Code execution | Yes | No |
Benchmarks
| Benchmark | GPT-5.5 | Muse Spark |
|---|---|---|
| SWE-bench Verified | 88.7 | 77.4 |
| Google-Proof Q&A | 93.6 | 89.5 |
| Chatbot Arena | 1488.0 | 1491.0 |
Deep dive
On shared benchmark coverage, SWE-bench Verified has GPT-5.5 at 88.7 and Muse Spark at 77.4, with GPT-5.5 ahead by 11.3 points; Google-Proof Q&A has GPT-5.5 at 93.6 and Muse Spark at 89.5, with GPT-5.5 ahead by 4.1 points; Chatbot Arena has GPT-5.5 at 1488 and Muse Spark at 1491, with Muse Spark ahead by 3 points. The largest visible gap is 11.3 points on SWE-bench Verified, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on structured outputs: GPT-5.5 and code execution: GPT-5.5. Both models share vision, multimodal input, reasoning mode, and function calling, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
Pricing coverage is uneven: GPT-5.5 has $5/1M input tokens and Muse Spark has no token price sourced yet. Provider availability is 2 tracked routes versus 0. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose GPT-5.5 when coding workflow support and broader provider choice are central to the workload. Choose Muse Spark when vision-heavy evaluation are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Is GPT-5.5 or Muse Spark open source?
GPT-5.5 is listed under Proprietary. Muse Spark is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, GPT-5.5 or Muse Spark?
Both GPT-5.5 and Muse Spark expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, GPT-5.5 or Muse Spark?
Both GPT-5.5 and Muse Spark expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for reasoning mode, GPT-5.5 or Muse Spark?
Both GPT-5.5 and Muse Spark expose reasoning mode. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for function calling, GPT-5.5 or Muse Spark?
Both GPT-5.5 and Muse Spark expose function calling. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Where can I run GPT-5.5 and Muse Spark?
GPT-5.5 is available on OpenAI API and OpenRouter. Muse Spark is available on the tracked providers still being sourced. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-14. Data sourced from public model cards and provider documentation.