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SpaceXAI · Language model

Grok 4.20

x-ai/grok-4.20
  • Language
Released Mar 31, 2026

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...

Specifications

Context window
2,000,000 tokens
Max output
1,800,000 tokens
Input
text, image, file
Output
text
Reasoning
supported
Tokenizer
Grok
Knowledge cutoff
2025-09-01

Supported parameters

Accepted by the model and forwarded as-is by the gateway.

  • logprobs
  • max_tokens
  • reasoning
  • response_format
  • seed
  • structured_outputs
  • temperature
  • tool_choice
  • tools
  • top_logprobs
  • top_p

Use it

POST /api/v1/chat/completions · MCP chat · full reference

curl https://omnirail.org/api/v1/chat/completions \
  -H "Authorization: Bearer $OMNIRAIL_KEY" -H "Content-Type: application/json" \
  -d '{"model":"x-ai/grok-4.20","messages":[{"role":"user","content":"Hello"}],"max_tokens":300}'