Side-by-side comparison · Coding & Dev Tools
Amp vs 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.
Comparing 3 tools, the maximum.
At a glance
Pick it if: Developers and engineering teams working on large codebases who want agents running in the background, not tied to their laptop.
Pick it if: Developers who already pay for an X Subscription or Grok and want a Claude Code-style agent included in it.
Pick it if: ChatGPT subscribers who want a coding agent without paying for a second subscription.
Overview
| Attribute | Amp | Grok Build | OpenAI Codex |
|---|---|---|---|
| In one line | A coding agent that keeps working on remote machines after you close your laptop. | xAI'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 model | Freemium | Paid | Freemium |
| Starting price | $20/mo | $8/mo | $8/mo |
| Free plan | Yes | No | Yes |
| Works with Claude Code | Yes | Yes | No |
Rating breakdown
Our scores out of 5. The higher bar in each row is highlighted.
| Attribute | Amp | Grok Build | OpenAI Codex |
|---|---|---|---|
| Overall rating | 4.0 | 3.5 | 4.2Winner |
| Ease of useHow quickly someone non-technical gets value from it. | 3.0 | 3.0 | 3.5 |
| FeaturesHow completely it covers its own job, and how well the pieces fit together. | 4.5 | 4.0 | 4.5 |
| Output qualityHow good the results are before you fix them. | 4.5 | 3.5 | 4.5 |
| Value for moneyWhat you get for the price, including the free plan. | 4.0 | 3.5 | 4.5 |
| Speed & reliabilityHow fast it is and how often it falls over. | 4.0 | 3.5 | 4.0 |
Feature comparison
A tick means it does this today. A dash means we haven't checked.
| Attribute | Amp | Grok Build | OpenAI Codex |
|---|---|---|---|
| Access & platform | |||
| Free plan | Yes | No | Yes |
| Mobile app | Yes | No | Yes |
| Desktop app | Yes | No | Yes |
| Browser extension | No | No | No |
| API access | Yes | Yes | Yes |
| Teams & business | |||
| Team workspace | Yes | Yes | Yes |
| Enterprise plan or SSO | Yes | Yes | Yes |
| Connects to other apps | Yes | Yes | Yes |
| Open source or self-hosted | Yes | Yes | Yes |
| AI abilities | |||
| Works with your files | Yes | Yes | Yes |
| Understands images | Yes | – | Yes |
| Makes images | No | No | No |
| Makes video | No | No | No |
| Writes code | Yes | Yes | Yes |
| Runs agents or automations | Yes | Yes | Yes |
| Learns your brand or style | – | – | Yes |
| Works in many languages | Yes | Yes | Yes |
| Capabilities score | 13/ 17 | 9/ 17 | 14/ 17 |
Pricing
Plans as listed on each vendor's site when we last checked. Confirm before you buy.
| Attribute | Amp | Grok Build | OpenAI Codex |
|---|---|---|---|
| Plans | HobbyOur pick Free Developers with their own model subscription or keys. | X Subscription Plus $8/mo Trying Grok Build alongside Grok and X Premium. | Free Free A quick look at what it can do. |
Megawatt $20/mo Individuals who want Amp to host the machines. | X Subscription PremiumOur pick $30/mo Developers who use Grok most days. | Go $8/mo Occasional light tasks. | |
Gigawatt $200/mo Heavy users running many big jobs. | Super / Ultra $100/mo or $200/mo Heavy users running agents all day. | PlusOur pick $20/mo Anyone who already pays for ChatGPT. | |
Enterprise Custom Large companies with security and compliance needs. | 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 pick | Start on Hobby and link a ChatGPT or Claude subscription you already pay for. Move to Megawatt at $20 a month only when you want Amp to host the machines so tasks run while you're away. Teams can create a workspace at no extra charge. | If 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
| Attribute | Amp | Grok Build | OpenAI Codex |
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Pros and cons
| Attribute | Amp | Grok Build | OpenAI Codex |
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Who each one is for
| Attribute | Amp | Grok Build | OpenAI Codex |
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Questions people ask
Which is better, Amp, Grok Build or OpenAI Codex?
OpenAI Codex scores highest overall in our ratings (Amp 4.0/5, Grok Build 3.5/5 and OpenAI Codex 4.2/5). Amp is best for running several coding tasks in the background at once and working on big, messy codebases. 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, Amp, Grok Build or OpenAI Codex?
Amp: There's a free plan, and paid plans start at $20/mo. 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, Amp, 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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