GPT-5.6 Terra is a balanced model in OpenAI's GPT-5.6 series, positioned between the flagship Sol tier and the cost-efficient Luna tier. It is suited for everyday coding, reasoning, and agentic...
Model details →OpenAI: GPT-5.6 Terra vs SpaceXAI: Grok 4.20
SpaceXAI: Grok 4.20 wins on 2 of 6 axes — pricing and capability skew in its favour for most workloads.
Grok 4.20 is a reasoning model from SpaceXAI with industry-leading speed and agentic tool calling capabilities. It combines the lowest hallucination rate on the market with strict prompt adherance, delivering...
Model details →Side-by-side comparison
| Capability | OpenAI: GPT-5.6 Terra | SpaceXAI: Grok 4.20 | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 1.1M | 2M | 🏆 SpaceXAI: Grok 4.20 |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $1.00 | $1.25 | 🏆 OpenAI: GPT-5.6 Terra |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $6.00 | $2.50 | 🏆 SpaceXAI: Grok 4.20 |
| Tool / function calling First-class support for emitting structured tool calls. | Yes | Yes | Tie |
| Vision input Accepts image inputs alongside text. | Yes | Yes | Tie |
| Reasoning mode Internal chain-of-thought / extended-thinking support. | Yes | Yes | Tie |
Frequently asked questions
Is OpenAI: GPT-5.6 Terra better than SpaceXAI: Grok 4.20?
SpaceXAI: Grok 4.20 wins on 2 of 6 axes — pricing and capability skew in its favour for most workloads.
What's the price difference between OpenAI: GPT-5.6 Terra and SpaceXAI: Grok 4.20?
Input: $1.00 vs $1.25 per 1M tokens. Output: $6.00 vs $2.50 per 1M tokens.
What context windows do OpenAI: GPT-5.6 Terra and SpaceXAI: Grok 4.20 support?
OpenAI: GPT-5.6 Terra supports up to 1.1M tokens. SpaceXAI: Grok 4.20 supports up to 2M tokens.
Do both OpenAI: GPT-5.6 Terra and SpaceXAI: Grok 4.20 support tool calling?
OpenAI: GPT-5.6 Terra: yes. SpaceXAI: Grok 4.20: yes.
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