Grok 4.20 Reasoning
Grok 4.20 Reasoning is worth evaluating for rag, agents, and long context when its provider route and context window match the workload.
Use it for
- Teams evaluating rag, agents, and long context
- Workloads that can use a 1m context window
- Buyers comparing 2 tracked provider routes
Do not use it for
- Workloads where another current model has stronger sourced task evidence
- Family
- Grok 4
- Released
- 2026-03-10
- Context
- 1m
- Knowledge cutoff
- 2024-11
- Specialization
- reasoning
- Openness
- Proprietary
- License
- ProprietaryCommercial use: conditional
Cheapest of 2 routes · Vercel AI Gateway · cache read $0.200
About
Grok 4.20 Reasoning is the xAI API reasoning variant launched around March 10, 2026 as grok-4.20-0309-reasoning. The prior May 2026 seed date was a placeholder; this model was already available months earlier and remains active.
Grok 4.20 Reasoning is a proprietary model in the Grok 4 family. The structured metadata tracks a 1m-token context window, multimodal input, reasoning, function calling, tool use, and structured outputs. This page tracks provider routes through xAI Console and Vercel AI Gateway, with the cheapest tracked route listed at $1.25 input and $2.5 output per 1M tokens. Headline tracked benchmarks include Google-Proof Q&A 88.5 and Humanity's Last Exam 30.0.
Top use-case fit: coding, agents, and build tasks
RAG
Included by capability and metadata signals in the decision map.
Agents
Included by capability and metadata signals in the decision map.
Long context
Included by capability and metadata signals in the decision map.
Provider price ladder
Compare all 2Compare API pricing across 2 providers for input and output tokens, batch, and cached reads when available.
| Provider | Input / 1M | Output / 1M | Cache | Route |
|---|---|---|---|---|
| Vercel AI Gateway | $1.25 | $2.50 | read $0.200 | Serverless |
| xAI Console | $1.25 | $2.50 | - | Serverless |
Available via routers & gateways(1)
Capabilities
Benchmark peer barsfor RAG
No task-mapped benchmark peers are available for this model yet.
Benchmark scores(2)
| Benchmark | Score | Version | Source |
|---|---|---|---|
| Google-Proof Q&A | 88.5 | GPQA Diamond (accuracy) | https://designforonline.com/ai-models/xai-grok-4-20-0309-reasoning/ |
| Humanity's Last Exam | 30.0 | HLE for Grok 4 (accuracy) | https://designforonline.com/ai-models/xai-grok-4-20-0309-reasoning/ |
Migration checks
No linked migration route is available for this model yet.
Frequently asked questions
What is the context window of Grok 4.20 Reasoning?
Grok 4.20 Reasoning has a context window of 1m tokens.
How much does Grok 4.20 Reasoning cost?
Grok 4.20 Reasoning is available at $1.25/1M input tokens through xAI Console.
When was Grok 4.20 Reasoning released?
Grok 4.20 Reasoning was released on 2026-03-10.
Which providers offer Grok 4.20 Reasoning?
Grok 4.20 Reasoning is available from 2 providers: xAI Console, Vercel AI Gateway.
What benchmarks has Grok 4.20 Reasoning been tested on?
Grok 4.20 Reasoning has been evaluated on 2 benchmarks, including Google-Proof Q&A, Humanity's Last Exam.
Cheapest of 2 routes · Vercel AI Gateway · cache read $0.200