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Side-by-side comparison · Coding & Dev Tools

Grok Build vs OpenAI Codex

Everything that matters when choosing between them, in one place: our rating, what each can do, what they cost, and the trade-offs.

Grok Build

3.5

From $8/mo

Best overall

OpenAI Codex

4.2

From $8/mo

Comparing 2 tools. Add one more if you like.

At a glance

Pick it if: Developers who already pay for an X Subscription or Grok and want a Claude Code-style agent included in it.

Best overallBest valueEasiest to use

Pick it if: ChatGPT subscribers who want a coding agent without paying for a second subscription.

Overview

AttributeGrok BuildOpenAI Codex
In one linexAI's open-source terminal coding agent, included in every paid X Subscription plan.OpenAI's coding agent. Hand it a task and it works away while you do other things.
Pricing modelPaidFreemium
Starting price$8/mo$8/mo
Free plan No Yes
Works with Claude Code Yes No

Rating breakdown

Our scores out of 5. The higher bar in each row is highlighted.

AttributeGrok BuildOpenAI Codex
Overall rating3.54.2Winner
Ease of useHow quickly someone non-technical gets value from it.
3.0
3.5
FeaturesHow completely it covers its own job, and how well the pieces fit together.
4.0
4.5
Output qualityHow good the results are before you fix them.
3.5
4.5
Value for moneyWhat you get for the price, including the free plan.
3.5
4.5
Speed & reliabilityHow fast it is and how often it falls over.
3.5
4.0

Feature comparison

A tick means it does this today. A dash means we haven't checked.

AttributeGrok BuildOpenAI Codex
Access & platform
Free plan No Yes
Mobile app No Yes
Desktop app No Yes
Browser extension No No
API access Yes Yes
Teams & business
Team workspace Yes Yes
Enterprise plan or SSO Yes Yes
Connects to other apps Yes Yes
Open source or self-hosted Yes Yes
AI abilities
Works with your files Yes Yes
Understands images– Yes
Makes images No No
Makes video No No
Writes code Yes Yes
Runs agents or automations Yes Yes
Learns your brand or style– Yes
Works in many languages Yes Yes
Capabilities score9/ 1714/ 17

Pricing

Plans as listed on each vendor's site when we last checked. Confirm before you buy.

AttributeGrok BuildOpenAI Codex
Plans

X Subscription Plus

$8/mo

Trying Grok Build alongside Grok and X Premium.

Free

Free

A quick look at what it can do.

X Subscription PremiumOur pick

$30/mo

Developers who use Grok most days.

Go

$8/mo

Occasional light tasks.

Super / Ultra

$100/mo or $200/mo

Heavy users running agents all day.

PlusOur pick

$20/mo

Anyone who already pays for ChatGPT.

xAI API

Pay as you go

CI pipelines and people who prefer paying per use.

Pro

From $100/mo

Developers who hit the Plus limits.

Business

$20/user/mo billed yearly, or $25 monthly

Teams of 2 or more.

Enterprise

Custom

Large organisations.

Which plan to pickIf you already pay for X, try it on the plan you have. Premium at $30 a month is the sensible level for regular coding, but if you're choosing a coding agent from scratch, Claude Code or Codex are the safer picks today. Plans changed on 12 October 2026, so check x.ai before you buy.If you already have ChatGPT Plus, you have Codex: just try it. If you are choosing between this and Claude Code with no existing subscription, Plus at $20 and Claude Pro at $20 cost the same, so pick whichever chat assistant you prefer. If you outgrow Plus, Pro starts at $100 and has no five-hour limit for now. The $200 tier gives new subscribers less usage than it used to, and Ultrafast mode is only on the $500 tier.

Key features

AttributeGrok BuildOpenAI Codex
Standout features
  • Full-screen terminal agent
  • Headless mode
  • Skills, plugins and MCP
  • Works in editors
  • Open source
  • Cloud tasks
  • Desktop app and CLI
  • Start from your phone
  • Automatic code review
  • AGENTS.md
  • Open source CLI

Pros and cons

AttributeGrok BuildOpenAI Codex
Pros
  • Included in X Subscription plans from $8 a month
  • Open source under Apache 2.0
  • Supports MCP servers, skills, plugins and hooks
  • Headless mode for scripts and CI
  • Included with every ChatGPT plan, so many people already have it
  • Cloud tasks let you start work from anywhere and come back later
  • Strong on tough, multi-file coding jobs
  • The CLI is open source and works with an API key
Cons
  • New, with little independent review yet
  • Grok's coding quality hasn't been shown to match Claude or GPT
  • Plans and access rules have changed several times since launch
  • Terminal-first, so less friendly for non-developers
  • Five-hour and weekly limits bite on Plus if you use it seriously
  • Cloud tasks use more of your allowance than local ones
  • It asks fewer questions than Claude Code before changing things
  • Model names and limits change often, which makes it hard to plan costs
  • The $200 Pro tier now gives new subscribers less usage than before

Who each one is for

AttributeGrok BuildOpenAI Codex
Best for
  • X Subscription users who want a coding agent included
  • Trying Grok models on real coding work
  • Developers who want an open-source agent they can inspect
  • Running agents in scripts and CI
  • Background tasks in the cloud
  • Starting a task from your phone
  • Developers already on ChatGPT Plus
  • Coding in the terminal
You'll find it used by
  • Developers
  • X power users
  • Open-source fans
  • ChatGPT subscribers
  • Developers
  • Startup teams
  • Solo founders

Questions people ask

Which is better, Grok Build or OpenAI Codex?

OpenAI Codex scores highest overall in our ratings (Grok Build 3.5/5 and OpenAI Codex 4.2/5). Grok Build is best for X Subscription users who want a coding agent included and Trying Grok models on real coding work. OpenAI Codex is best for background tasks in the cloud and starting a task from your phone.

Which is cheaper, Grok Build or OpenAI Codex?

Grok Build: There's no free plan. Paid plans start at $8/mo. OpenAI Codex: There's a free plan, and paid plans start at $8/mo.

Which is easier to use, Grok Build or OpenAI Codex?

OpenAI Codex rates highest for ease of use in our scores. ChatGPT subscribers who want a coding agent without paying for a second subscription.

How we compare

Ratings are our own, from using each tool, across ease of use, features, output quality, value for money, speed & reliability.

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