Grok 4.3 is xAI’s budget frontier play: an AA Intelligence Index of 53 — within striking distance of the leaders — at just $1.25 / $2.50 per 1M tokens. It leads xAI’s lineup on agentic tool calling, instruction following and a self-reported non-hallucination rate.
Per xAI’s docs it ships a 1M-token context, text and image input, function calling, structured outputs and configurable reasoning effort, which makes it a practical engine for cost-conscious agent builds.
Two caveats: it sits a notch below Opus 4.8, GPT-5.5 and Gemini 3.1 Pro on raw intelligence, and Grok’s strongest capabilities are reserved for the $300/month SuperGrok Heavy tier rather than the standard API.
Successor: xAI launched Grok 4.5 on July 8, 2026 as the coding-and-agent flagship ($2 / $6 per 1M, 500K context, default in Grok Build and Cursor). Keep 4.3 when you need the cheaper 1M window or lower token rates; route hard agent loops to 4.5.
Best for
- Price-sensitive agentic builds
- Tool-calling pipelines within a 1M window
- Real-time, X-integrated assistants
Pros & cons
Strengths
- Frontier-adjacent intelligence (AA Index 53) at a budget price
- Strong agentic tool calling, function calling and structured outputs
- Configurable reasoning effort
Limitations
- Trails the top three on overall intelligence
- Best features gated behind a costly SuperGrok Heavy tier