Cracked AI Engineering

GPT OSS 20B vs Grok 4

Grok 4 offers 256K tokens context vs 131K tokens, GPT OSS 20B is more cost-effective, GPT OSS 20B has open weights. Compare full specs, pricing, and choose the best model for your use case.

Quick Overview

GPT OSS 20B

FastRouter

131K tokens context • $0.05 / $0.20 per 1M tokens

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Grok 4

FastRouter

256K tokens context • $3.00 / $15.00 per 1M tokens

View full specifications →

Detailed Comparison

Specification
GPT OSS 20B
Grok 4
Provider
FastRouter
FastRouter
Context Window
131K tokens
256K tokens
Max Output Tokens
66K tokens
64K tokens
Input Pricing (per 1M tokens)
$0.05
$3.00
Output Pricing (per 1M tokens)
$0.20
$15.00
Release Date
Aug 2025
Jul 2025

Capabilities

Capability
GPT OSS 20B
Grok 4
Text Generation
Function Calling
Advanced Reasoning

Which Model Should You Choose?

Choose GPT OSS 20B if:

  • • Cost efficiency is a priority
  • • You prefer open weights

Choose Grok 4 if:

  • • You need a larger context window