Grok 4.3 vs Grok Code Fast 1
xAI · US | xAI · US · Updated June 2026
Quick verdict
Both are xAI models. Grok 4.3 is the newer, generally stronger default; reach for Grok Code Fast 1 when its lower price or a specific cost or latency profile matters more than the latest capabilities.
Grok 4.3 and Grok Code Fast 1 are both xAI models, so the real question is not which lab to trust but which tier fits your workload and budget. Grok 4.3 is the current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5. Grok Code Fast 1 is xAI's speed-tier coding model at $0.20/$1.50 with a 256K window — cheap, fast agentic code over frontier quality. Since both come from the same lab, the comparison below focuses on the tier-and-cost trade-offs that actually separate them.
Key differences at a glance
- ▸Price: Grok Code Fast 1 is about 6.3× cheaper on input ($0.2/$1.5 per 1M tokens vs $1.25/$2.5 per 1M tokens) — a large enough gap that at scale it can be the single biggest line item in the decision.
- ▸Context window: Grok 4.3 holds 3.9× more — 1M (~1,500 pages) vs 256K (~384 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
- ▸Recency: Grok 4.3 is the newer model by about 8 months (released April 30, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | Grok 4.3 | Grok Code Fast 1 |
|---|---|---|
| Provider | xAI (US) | xAI (US) |
| Released | April 30, 2026 | August 28, 2025 |
| Context window | 1M (~1,500 pages) | 256K (~384 pages) |
| Price (in/out) | $1.25/$2.5 per 1M tokens | $0.2/$1.5 per 1M tokens |
| Open weight? | No — API only | No — API only |
| Modalities | text, image, video, code | text, code |
| SWE-Bench Verified | Not published | Not published |
| MRCR v2 @ 1M | Not published | Not published |
Who wins what
Video understanding from native video input
Grok 4.3
Grok Code Fast 1 is comparatively weak here — text and code only — no image, audio or video input
Generating PDF, PPTX, and XLSX files directly
Grok 4.3
The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5 — and it carries the larger 1M context.
Real-time questions using live X data
Grok 4.3
The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5 — and it is the newer of the two.
Fast, cheap agentic coding at $0.20/$1.50
Grok Code Fast 1
At $0.2/$1.5 per 1M tokens it undercuts Grok 4.3 ($1.25/$2.5 per 1M tokens), and that gap compounds at volume.
Low-latency code generation and terminal tasks
Grok Code Fast 1
XAI's speed-tier coding model at $0.20/$1.50 with a 256K window — cheap, fast agentic code over frontier quality — and it runs cheaper at $0.2/$1.5 per 1M tokens.
High-volume coding pipelines where speed beats peak quality
Grok Code Fast 1
Grok Code Fast 1 lists high-volume coding pipelines where speed beats peak quality among its strengths; Grok 4.3 does not.
Lowest cost at scale
Grok Code Fast 1
At $0.2/$1.5 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input
Grok 4.3
Its 1M window is about 3.9× larger than Grok Code Fast 1's 256K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Grok Code Fast 1
At $0.2/$1.5 per 1M tokens it undercuts Grok 4.3, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Grok 4.3
Larger 1M window fits more in one prompt.
Anyone whose priority is video understanding from native video input
→ Grok 4.3
It is specifically built for that.
Anyone whose priority is fast, cheap agentic coding at $0.20/$1.50
→ Grok Code Fast 1
That is its strongest area.
Grok 4.3: where it fits
The current xAI flagship: 1M context, native video input, file generation, and live X data, ahead of the still-unreleased Grok 5. Released April 30, 2026 by xAI, it is built for video understanding from native video input, generating PDF, PPTX, and XLSX files directly, real-time questions using live X data, and long-context, multi-agent reasoning.
Its trade-offs are real: higher context pricing on requests above 200K tokens, and less independent benchmark coverage than OpenAI, Anthropic, or Google. At $1.25 in / $2.5 out per million tokens, it sits in the mid price band.
Grok Code Fast 1: where it fits
XAI's speed-tier coding model at $0.20/$1.50 with a 256K window — cheap, fast agentic code over frontier quality. Released August 28, 2025 by xAI, it is built for fast, cheap agentic coding at $0.20/$1.50, low-latency code generation and terminal tasks, high-volume coding pipelines where speed beats peak quality, and a 256K window sized for real codebases.
Its trade-offs: text and code only — no image, audio or video input, xAI did not publish a SWE-Bench Verified score, a speed-tier coding model, not a frontier reasoner, and narrow focus — built for code, not general knowledge work. At $0.2 in / $1.5 out per million tokens, it sits in the budget price band.
The bottom line for this matchup
Because Grok 4.3 and Grok Code Fast 1 come from the same lab (xAI), they share the same training philosophy and ecosystem — the decision is purely tier vs. cost. Grok 4.3 is the more capable, more recent option; the other earns its place only when its price or latency profile fits a specific job better. Most teams should default to Grok 4.3 and drop down only with a concrete reason.
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See pricingFrequently asked questions
Is Grok 4.3 or Grok Code Fast 1 better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Grok 4.3 leans toward video understanding from native video input while Grok Code Fast 1 leans toward fast, cheap agentic coding at $0.20/$1.50, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Grok 4.3 or Grok Code Fast 1?
Grok Code Fast 1 is cheaper — $1.25/$2.5 per 1M tokens vs $0.2/$1.5 per 1M tokens, roughly 6.3× apart on input.
Which has the bigger context window?
Grok 4.3 — 1M vs 256K, about 3.9× larger. Useful only if the model actually reasons over the full window, which not all do.
Should I upgrade from Grok Code Fast 1 to Grok 4.3?
Since both are xAI models, the newer one (Grok 4.3) is usually the better default unless you need a specific cost or latency profile from the other.
Which is newer, Grok 4.3 or Grok Code Fast 1?
Grok 4.3 — released April 30, 2026, about 8 months after Grok Code Fast 1.
Related comparisons
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.