GPT-5.4 Mini vs Grok Code Fast 1

Our 12-test benchmark suite gives a clear picture: GPT-5.4 Mini wins 8 categories, Grok Code Fast 1 wins 1, and 3 are tied.

Where GPT-5.4 Mini leads:

• Structured output (5 vs 4): GPT-5.4 Mini ties for 1st among 54 models tested; Grok Code Fast 1 ranks 26th. For applications relying on JSON schema compliance — API integrations, data extraction pipelines — this gap matters.
• Long context (5 vs 4): GPT-5.4 Mini ties for 1st among 55 models; Grok Code Fast 1 ranks 38th. GPT-5.4 Mini also has a substantially larger context window (400K vs 256K tokens), reinforcing this advantage for document analysis and RAG workflows.
• Faithfulness (5 vs 4): GPT-5.4 Mini ties for 1st among 55 models; Grok Code Fast 1 ranks 34th. Fewer hallucinations relative to source material — critical for summarization and retrieval tasks.
• Strategic analysis (5 vs 3): One of the wider score gaps. GPT-5.4 Mini ties for 1st among 54 models; Grok Code Fast 1 ranks 36th. For nuanced tradeoff reasoning and business analysis, this is a meaningful difference.
• Multilingual (5 vs 4): GPT-5.4 Mini ties for 1st among 55 models; Grok Code Fast 1 ranks 36th. For non-English workloads, GPT-5.4 Mini is the stronger choice.
• Persona consistency (5 vs 4): GPT-5.4 Mini ties for 1st among 53 models; Grok Code Fast 1 ranks 38th. Relevant for chatbots and role-consistent assistant deployments.
• Creative problem solving (4 vs 3): GPT-5.4 Mini ranks 9th of 54; Grok Code Fast 1 ranks 30th. The gap here points to more specific and feasible ideation from GPT-5.4 Mini.
• Constrained rewriting (4 vs 3): GPT-5.4 Mini ranks 6th of 53; Grok Code Fast 1 ranks 31st. Compression within hard character limits favors GPT-5.4 Mini significantly.

Where Grok Code Fast 1 leads:

• Agentic planning (5 vs 4): Grok Code Fast 1 ties for 1st among 54 models (with 14 others); GPT-5.4 Mini ranks 16th. Goal decomposition and failure recovery in multi-step agentic workflows is Grok Code Fast 1's strongest differentiator. Combined with its reasoning token visibility (a quirk noted in the payload), this makes it well-suited for developers who want to inspect and steer reasoning in coding agents.

Tied categories:

• Tool calling (4 vs 4): Both rank 18th of 54. Neither has an edge on function selection and argument accuracy.
• Classification (4 vs 4): Both tie for 1st among 53 models. Equivalent routing and categorization capability.
• Safety calibration (2 vs 2): Both rank 12th of 55. Neither model stands out on refusing harmful requests while permitting legitimate ones — this score is below the field median (p50 = 2, but p25 = 1, so both sit at the median).

The cost difference between these two models is material at scale. GPT-5.4 Mini is priced at $0.75 input / $4.50 output per million tokens. Grok Code Fast 1 runs at $0.20 input / $1.50 output per million tokens — roughly 75% cheaper on input and 67% cheaper on output.

At 1M output tokens/month: GPT-5.4 Mini costs $4.50 vs Grok Code Fast 1's $1.50 — a $3 difference that's negligible for most projects.

At 10M output tokens/month: $45 vs $15 — a $30/month gap that starts to matter for budget-conscious teams.

At 100M output tokens/month: $450 vs $150 — a $300/month difference that becomes a real line item for production systems.

Developers running high-throughput agentic coding pipelines — the specific use case Grok Code Fast 1 is optimized for — should weigh whether GPT-5.4 Mini's broader benchmark wins justify the 3x output cost premium. For low-volume or mixed workloads, the quality advantage of GPT-5.4 Mini likely outweighs the price gap. Note also that Grok Code Fast 1 caps max output at 10,000 tokens versus GPT-5.4 Mini's 128,000, which affects cost calculations for long-generation tasks.

Choose GPT-5.4 Mini if:

• Your workload involves long documents, RAG, or retrieval at 30K+ tokens — it scores 5/5 on long context (tied 1st of 55) vs Grok Code Fast 1's 4/5 (38th of 55), and its 400K context window gives you more headroom.
• You need reliable structured output for JSON-heavy pipelines — 5/5 (tied 1st of 54) vs Grok Code Fast 1's 4/5 (26th of 54).
• You're working in non-English languages — 5/5 (tied 1st of 55) vs 4/5 (36th of 55).
• Strategic analysis, faithfulness to source material, or creative problem solving are central to your use case — GPT-5.4 Mini wins all three by a meaningful margin.
• You need up to 128,000 output tokens per request; Grok Code Fast 1 caps at 10,000.
• You accept text and image inputs — GPT-5.4 Mini supports multimodal input; Grok Code Fast 1 is text-only per the payload.

Choose Grok Code Fast 1 if:

• You're building agentic coding pipelines specifically — it scores 5/5 on agentic planning (tied 1st of 54) and its reasoning traces are visible in the response, letting you steer the model mid-task.
• Cost is a constraint at high volume — $1.50/M output tokens vs $4.50/M is a 3x saving that compounds at 10M+ tokens/month.
• Your outputs are short (under 10,000 tokens per request) and your tasks are coding-focused — Grok Code Fast 1 is purpose-built for this profile.
• You want logprobs or top_p control — parameters available on Grok Code Fast 1 but not listed for GPT-5.4 Mini in the payload.