xAI model

Grok 4.20

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...

xAIVerified 05/10/2026Released 31/03/2026

01 / decision

Decision snapshot

Each figure sits next to the middle of the field, so it can be read as dear or cheap, wide or narrow, rather than floating on its own. Compared against the 370 models tracked here, not against an absolute standard.

Capability

Not measured

No published benchmark scores yet

Input / 1M tokens

$1.25

field median $0.40

Output / 1M tokens

$2.50

field median $1.68

Context

2,000K

field median 262K

02 / overview

What Grok 4.20 is, and when to reach for it

Four questions, answered separately, because somebody arrives at one of them rather than at the top of the page.

This model has no written explanation yet.

The page is created the moment a model appears in a provider's catalogue, and the writing follows. Until then the measured sections below are the whole page.

What counts as evidence

Superseded by Grok 4.20 Multi-Agent. See the whole line.

03 / evidence

How much of this is verified

Split by category, so a strong number never hides a thin evidence base. Verified means it was read on the benchmark's own published results; a provider's claim about its own model is shown and labelled rather than dropped.

No published benchmark scores for this model yet.

A score is published only where the result can be verified. Until a benchmark result for this model exists in a source the tracker reads, this section stays empty rather than being filled with a provider's marketing figure.

What counts as evidence

04 / ledger

Benchmark ledger

Every published row, grouped by category, each compared with the best published score on the same benchmark. 'Is 64% good' is a question nobody can answer; '26 points behind the leader' is one anybody can.

Nothing in the ledger yet.

Each row here carries a score, the benchmark it came from, what the leading model scored on the same test, and a link to the published result. Rows appear as results are published and read.

What counts as evidence

05 / capability

Capability shape

Where this model is strong, and against how many peers. Ranks are against models with evidence in that category, not against every tracked model: ranking against models nobody tested would rank who published, not who is better.

No category scores to shape yet.

A category score is the weighted mean of the benchmarks published for it. With no published rows there is nothing to average, and an empty chart drawn at zero would say something false.

What counts as evidence

06 / cost

What it costs

List API rates as last read, each with the date it was confirmed, plus every change recorded since tracking began.

Grok 4.20 API pricingWriteWorks
ChargePriceUnitRead on
Input$1.25per 1M tokens2026-09-30
Output$2.50per 1M tokens2026-09-30
What a month costsWriteWorks
WorkloadInput / monthOutput / monthCost
A small product team20M tokens5M tokens$37.50
A busy support assistant200M tokens40M tokens$350.00
A document pipeline1000M tokens100M tokens$1,500.00

List API rates, no caching and no batch discount, which both providers offer and which change the answer a great deal. Treat these as the ceiling, not the bill.

07 / specs

Specifications

As listed by the provider's own catalogue and re-read every few hours. Anything absent is absent there too.

SpecificationWriteWorks
Context window2,000,000 tokens
Maximum output1,800,000 tokens
Modalitiestext, image, file
Released31/03/2026
StatusCurrent

08 / lineage

Lineage

What this model replaced, what replaced it, and what else its provider has in the field.

Also from xAI

All 8 xAI models

09 / line

The line

Every model in this family in release order, so a page from eight months ago says in one glance that two newer ones exist.

Came before

The first tracked in this line.

  1. 01Grok 4.2031/03/2026
  2. 02Grok 4.20 Multi-Agent31/03/2026
  3. 03Grok 4.330/04/2026
  4. 04Grok Latest08/07/2026
  5. 05Grok 4.508/07/2026
  6. 06Grok 4.612/08/2026
  7. 07Grok 4.721/09/2026

Ordered by release date and worked out from the naming, so a new member slots in as soon as its page exists. A retired model keeps its page and its place in the line.

10 / notes

WriteWorks notes

What this model changes for a brand trying to be cited in AI answers, and every change logged since it launched.

Change log

Every release, price and feature change for Grok 4.20, newest first. They also appear on the xAI page.

Nothing published here yet. Changes appear within hours of a provider announcing them.

11 / questions

Questions

The things people ask about this model, answered from what is on this page rather than from anywhere else.

What does Grok 4.20 cost?
$1.25 per million input tokens and $2.50 per million output tokens, as last read from the provider. The cost section works that into a monthly figure.
How current is this page?
The catalogue behind it is re-read every three hours, and the stamp at the top says when it last confirmed. A re-check that finds nothing changed updates that stamp and deliberately does not touch the page’s modified date.
Why are some sections empty?
Because nothing has been published that can be linked to. An empty section is better than a number you cannot check. The methodology sets out what counts.
WriteWorks

Is Grok 4.20 recommending you?

Models change what gets cited. WriteWorks tracks whether 10+ AI platforms, from ChatGPT and Claude to Gemini and Perplexity, name your brand or your competitors, and shows you the content gaps to close.