Codex Mini vs Grok Code Fast 1

Compare OpenAI and xAI AI models

OpenAI

Codex Mini

xAI

Grok Code Fast 1

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Cost Comparison (1000 input + 500 output tokens, 100 requests/day)

Codex Mini

Per Request:$0.004500

Daily:$0.45

Monthly:$13.50

Yearly:$164.25

Grok Code Fast 1

Per Request:$0.000950

Daily:$0.095

Monthly:$2.85

Yearly:$34.675

Cost Differences

$0.003550

Per Request

$0.355

Daily

$10.65

Monthly

$129.575

Yearly

Grok Code Fast 1 costs less than Codex Mini

Feature Comparison

Feature	Codex Mini	Grok Code Fast 1
Provider	OpenAI	xAI
Input Price	$1.50/1M tokens	$0.20/1M tokens
Output Price	$6.00/1M tokens	$1.50/1M tokens
Context Window	200,000 tokens	256,000 tokens
Max Output	32,768 tokens	32,768 tokens
Category	efficient	standard
Capabilities	textcodereasoning	textcodereasoning
Release Date	2/2/2026	2/1/2026

Codex Mini vs Grok Code Fast 1: Which Should You Choose?

Choosing between Codex Mini and Grok Code Fast 1 depends on your priorities: cost efficiency, context length, or raw capability. Grok Code Fast 1 is the more affordable option at $0.20/1M input tokens — 87% cheaper than Codex Mini. Meanwhile, Grok Code Fast 1 offers a significantly larger context window at 256,000 tokens vs 200,000 for Codex Mini.

These models come from different providers — OpenAI and xAI — which means different API ecosystems, SDKs, rate limits, and terms of service. If you're already integrated with OpenAI, switching to xAIinvolves migration effort beyond just pricing. Factor in your existing infrastructure when deciding.

These models target different tiers: Codex Mini is a efficient model while Grok Code Fast 1 is standard. This means they're optimized for different workloads. Grok Code Fast 1 targets more demanding workloads, while Codex Mini provides a cost-effective option for everyday tasks.

Output costs matter too. Codex Mini charges $6.00/1M output tokens vs $1.50 for Grok Code Fast 1. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. Grok Code Fast 1 has the edge here at $1.50/1M output tokens.

Best Use Cases

Choose Codex Mini when:

• You're already using OpenAI's API ecosystem
• You're running high-volume, latency-sensitive workloads

Choose Grok Code Fast 1 when:

• Budget is a primary concern
• You need a larger context window (256,000 tokens)
• You're already using xAI's API ecosystem

Try Different Scenarios

Use the calculator below to see how costs change with different usage patterns

Codex Mini (OpenAI)

Cost Calculator

Provider

Model

Input Tokens

Output Tokens

Requests/Day

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Grok Code Fast 1 (xAI)

Cost Calculator

Provider

Model

Input Tokens

Output Tokens

Requests/Day

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Start using Codex Mini today

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Frequently Asked Questions

Which is cheaper, Codex Mini or Grok Code Fast 1?▼

Grok Code Fast 1 is cheaper for input tokens at $0.20 per million tokens vs $1.50 for Codex Mini — that's 87% savings on input costs.

What is the context window difference between Codex Mini and Grok Code Fast 1?▼

Codex Mini supports 200,000 tokens while Grok Code Fast 1 supports 256,000 tokens — a difference of 56,000 tokens in favor of Grok Code Fast 1.

Which model is better for AI Agent / Agentic Workflows?▼

Both models support text, code, reasoning. For ai agent / agentic workflows, Grok Code Fast 1 is the lower-cost option, while Grok Code Fast 1 offers a larger context window (256,000 vs 200,000 tokens). Choose Grok Code Fast 1 for budget sensitivity or Grok Code Fast 1 for longer context tasks.

Which model has better overall pricing for heavy usage?▼

At 100 requests/day with 1,000 input and 500 output tokens each, Codex Mini costs about $13.50/month and Grok Code Fast 1 costs about $2.85/month. Overall, Grok Code Fast 1 has lower combined input + output rates ($0.20 in, $1.50 out) vs Codex Mini.