GPT-5.4-Cyber vs Grok 4.3
GPT-5.4-Cyber (2026) and Grok 4.3 (2026) are frontier-tier reasoning models from OpenAI and xAI. GPT-5.4-Cyber ships a not-yet-sourced context window, while Grok 4.3 ships a 1M-token context window. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing. The goal is to make the tradeoff clear before deeper testing.
Grok 4.3 is safer overall; choose GPT-5.4-Cyber when provider fit matters.
Decision scorecard
Local evidence first| Signal | GPT-5.4-Cyber | Grok 4.3 |
|---|---|---|
| Decision fit | Vision | RAG, Agents, and Long context |
| Context window | — | 1M |
| Cheapest output | - | $2.5/1M tokens |
| Provider routes | 0 tracked | 2 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Local decision data tags GPT-5.4-Cyber for Vision.
- Grok 4.3 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4.3 has broader tracked provider coverage for fallback and procurement flexibility.
- Grok 4.3 uniquely exposes Vision, Function calling, and Tool use in local model data.
- Local decision data tags Grok 4.3 for RAG, Agents, and Long context.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
GPT-5.4-Cyber
Unavailable
No complete token price in local provider data
Grok 4.3
$1,625
Cheapest tracked route: xAI Console
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for GPT-5.4-Cyber and Grok 4.3; plan for SDK, billing, or endpoint changes.
- Grok 4.3 adds Vision, Function calling, and Tool use in local capability data.
- No overlapping tracked provider route is sourced for Grok 4.3 and GPT-5.4-Cyber; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Vision, Function calling, and Tool use before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-14 | 2026-05-05 |
| Context window | — | 1M |
| Parameters | — | ~0.5T |
| Architecture | decoder only | - |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-08 | - |
Pricing and availability
| Pricing attribute | GPT-5.4-Cyber | Grok 4.3 |
|---|---|---|
| Input price | - | $1.25/1M tokens |
| Output price | - | $2.5/1M tokens |
| Providers | - |
Capabilities
| Capability | GPT-5.4-Cyber | Grok 4.3 |
|---|---|---|
| Vision | No | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | No | Yes |
| Tool use | No | Yes |
| Structured outputs | No | Yes |
| Code execution | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on vision: Grok 4.3, function calling: Grok 4.3, tool use: Grok 4.3, and structured outputs: Grok 4.3. Both models share multimodal input and reasoning mode, 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-5.4-Cyber has no token price sourced yet and Grok 4.3 has $1.25/1M input tokens. Provider availability is 0 tracked routes versus 2. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose GPT-5.4-Cyber when provider fit are central to the workload. Choose Grok 4.3 when vision-heavy evaluation and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency. For teams standardizing a stack, that distinction is often the difference between a benchmark win and a reliable deployment.
FAQ
Is GPT-5.4-Cyber or Grok 4.3 open source?
GPT-5.4-Cyber is listed under Proprietary. Grok 4.3 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-5.4-Cyber or Grok 4.3?
Grok 4.3 has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, GPT-5.4-Cyber or Grok 4.3?
Both GPT-5.4-Cyber and Grok 4.3 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-5.4-Cyber or Grok 4.3?
Both GPT-5.4-Cyber and Grok 4.3 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-5.4-Cyber or Grok 4.3?
Grok 4.3 has the clearer documented function calling signal in this comparison. If function calling is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run GPT-5.4-Cyber and Grok 4.3?
GPT-5.4-Cyber is available on the tracked providers still being sourced. Grok 4.3 is available on xAI Console and OpenRouter. 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.