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xAIGrok 4 familyLegacyReasoning modelReleased Mar 2026

Grok 4.20 (Reasoning / Non-reasoning / Multi-Agent)

Previous-generation Grok, notable for its multi-agent variant for deep research.

Model idgrok-4.20-0309-reasoning

Price$1.25 in, $2.50 out per 1M tokens

Checked29 September 2026

No published training cutoff

At least1,889events since its release in March 2026

85 historic, 433 major. 227 days of news.

xAI doesn’t publish a training cutoff, so we count from its release date. The real gap is larger.

How to call it

5 ways to use Grok 4.20 (Reasoning / Non-reasoning / Multi-Agent), with the model id each provider expects.

Providers, model ids, endpoints and docs for Grok 4.20 (Reasoning / Non-reasoning / Multi-Agent)
ProviderModel idEndpointDocs
xAI API grok-4.20-0309-reasoning https://api.x.ai/v1/chat/completions docs.x.ai
xAI API (non-reasoning) grok-4.20-0309-non-reasoning https://api.x.ai/v1/chat/completions
xAI API (multi-agent) grok-4.20-multi-agent-0309 docs.x.ai
OpenRouter x-ai/grok-4.20 openrouter.ai
OpenRouter (multi-agent) x-ai/grok-4.20-multi-agent openrouter.ai

Pricing

Prices for Grok 4.20 (Reasoning / Non-reasoning / Multi-Agent)
Input$1.25 per 1M tokens
Cached input$0.20 per 1M tokens
Output$2.50 per 1M tokens
Input, prompts over 200K tokens$2.50 per 1M tokens
Output, prompts over 200K tokens$5 per 1M tokens

As published: “per 1M tokens (USD)”.

Source: docs.x.ai, checked 29 September 2026.

Specs

Input
Text and images
Output
Text
Context window
1,000,000 tokens
Max output
Not published
Open weights
No
Licence
Proprietary
Training cutoff
Not published
Released
March 2026
Status
Legacy
Type
Reasoning model

What stands out

What its maker marketed at launch, and what people found later, each with its source.

  • Multi-agent model variant

    Dedicated API id that runs parallel collaborating agents (4 at low/medium effort, 16 at high/xhigh) that search and cross-check before synthesizing an answer.

    Source: docs.x.ai

  • Reasoning and non-reasoning twin ids

    Same snapshot (0309) offered as separate reasoning and non-reasoning model ids.

    Source: docs.x.ai

Notes

Snapshot ids dated 0309. xAI docs list 1M context; OpenRouter lists 2M. Superseded by Grok 4.5-4.7; logprobs unsupported.

curl https://api.x.ai/v1/chat/completions -H "Authorization: Bearer $XAI_API_KEY" -H "Content-Type: application/json" \
 -d '{"model":"grok-4.20-0309-reasoning","messages":[{"role":"user","content":"Hello"}]}'

Sources: https://docs.x.ai/docs/models , https://docs.x.ai/developers/model-capabilities/text/multi-agent