Title: Carbon.txt Author: Nahuai Badiola Published: November 12, 2026 Last modified: November 12, 2026 --- Search plugins ![](https://s.w.org/plugins/geopattern-icon/carbon-txt.svg) # Carbon.txt By [Nahuai Badiola](https://profiles.wordpress.org/nahuai/) [Download](https://downloads.wordpress.org/plugin/carbon-txt.0.5.zip) * [Details](https://wordpress.org/plugins/carbon-txt/#description) * [Reviews](https://wordpress.org/plugins/carbon-txt/#reviews) * [Installation](https://wordpress.org/plugins/carbon-txt/#installation) * [Development](https://wordpress.org/plugins/carbon-txt/#developers) [Support](https://wordpress.org/support/plugin/carbon-txt/) ## Description carbon.txt is a single, recognisable place on your website, at https://your-site. com/carbon.txt, where anyone can find out what your organisation publishes about its own environmental impact. This plugin builds that file for you. You describe your disclosures (the public documents where you report your sustainability data) and the plugin turns them into a valid `carbon.txt`, served straight from your site. **What you can do with it:** * **Add your disclosures.** One or more links to the documents that back up your claims: your annual report, your sustainability page, a certificate, and so on. Each one gets a document type, so readers know what they are looking at. * **Point at any document.** Paste a URL, pick one of your published pages, or choose a file from your media library. * **Record your certifications.** If your organisation holds a certification ( a B Corp, an ecolabel, an ISO standard), list it once and link your disclosures to it. * **Preview before you publish.** The settings screen shows the exact file that will be served, so you always know what visitors will get. * **Start from what you already have.** If a `carbon.txt` already exists on your server, the plugin can read it and offer to import what it finds. * **Keep a copy.** Your disclosures stay saved when you deactivate the plugin, and you can copy or download them at any time. ### How it works **Document types.** The picker offers the document types the `carbon.txt` syntax defines. The Green Web Foundation has deprecated the “web page” type in favour of“ sustainability page”, so it is no longer offered, and new disclosures start at “ sustainability page”. Disclosures that already use “web page” keep working. They are labelled as deprecated in the editor, so you can move them on when you get the chance. **Required fields.** A disclosure needs a URL, and a certification needs a title and a URL. Anything still missing one of those is skipped when you save. The editor marks every field as required or optional, and tells you what was left out. **Certifications.** Each certification you list gets an id generated from its title, and your disclosures reference that id. Only complete certifications appear in the list you can choose from, so a half-finished one never shows up as a blank entry. **The file itself.** It is generated on request from your settings and cached, so there is no physical file to manage and it survives deploys. It is served from your site root even with plain permalinks. Every save re-stamps the `last_updated` date. **An existing file on your server.** If a `carbon.txt` already exists at your domain root or at `/.well-known/carbon.txt`, the settings screen warns you: your web server may keep serving that file instead of the one this plugin generates. You can import the disclosures it finds, and the old file is then permanently deleted once you save. **DNS delegation.** If your domain has a `carbon-txt-location` TXT record (see https://carbontxt.org/faq), that takes priority over any file this plugin generates. The settings screen warns you when it finds one, so you are not left wondering why your changes seem to have no effect. **Validation.** After each save, the plugin asks the Green Web Foundation’s hosted validator to check your domain. Their validator fetches your live carbon.txt from the web, so this needs a publicly reachable site. Local and staging domains are skipped. No key or setup is required, and validation can be switched off from the settings screen. See “External services” below for exactly what is sent, and where. **Removing the plugin.** Deactivating keeps your disclosures and settings. Deleting the plugin removes them, so the plugin offers to copy or download your file first. ### External services This plugin connects to the carbon.txt validator API operated by The Green Web Foundation, to check that the carbon.txt file your site publishes can be read from the public web. That check is the only thing it is used for. **What is sent.** Your site’s fully-qualified domain name — for example example. com — together with the shared API key that identifies this plugin. No file contents, no page content, no visitor or user data, and nothing that identifies you. **When.** Once per save of this plugin’s settings, and only while the “Validate with the Green Web Foundation after saving” option is ticked. It is skipped on domains that are not publicly reachable, such as local and staging sites. Untick it in the settings and nothing is sent. **Where.** From your WordPress server, over HTTPS, to https://carbon-txt-api.greenweb. org/. The validator then fetches https://your-domain/carbon.txt itself, which is why a passing result tells you the file is publicly readable rather than blocked by a firewall, CAPTCHA or CDN. The Green Web Foundation also uses the aggregate results to measure adoption of the carbon.txt standard. This service is provided by The Green Web Foundation: * Terms of use and API usage conditions: https://developers.thegreenwebfoundation. org/api/carbon-txt/overview/ * Privacy policy: https://www.thegreenwebfoundation.org/privacy-statement/ * Service documentation: https://developers.thegreenwebfoundation.org/api/carbon- txt/ ### Development This plugin is developed in the open on [GitHub](https://github.com/thegreenwebfoundation/wp-carbon-txt-plugin). Bug reports, questions and pull requests are welcome there. The admin app’s source lives in `src/`. Build it with: ``` npm install && npm run build ``` ## Installation 1. Upload the plugin to `/wp-content/plugins/carbon-txt/`, or install the zip from** Plugins > Add New > Upload Plugin** in your dashboard. 2. Activate the plugin. 3. Go to **Settings > Carbon.txt** and add your first disclosure. 4. Press **Save and publish**. Your `carbon.txt` is now live at https://your-site. com/carbon.txt. ## FAQ ### Does this plugin create a file on my server? No. The file is generated when a visitor requests it, and served from your site root. There is nothing to upload and nothing to clean up. ### Why is my carbon.txt not the one I just saved? Usually one of three things. A `carbon.txt` file already sitting on your server is being served directly, a `carbon-txt-location` DNS record is delegating discovery elsewhere, or you are on a local or staging domain that isn’t publicly reachable. The settings screen warns you about the first two. ### What happens to my disclosures if I delete the plugin? They are removed with it. Deactivating keeps them, and you can copy or download your file from the settings screen at any time. ## Reviews There are no reviews for this plugin. ## Contributors & Developers “Carbon.txt” is open source software. The following people have contributed to this plugin. Contributors * [ Nahuai Badiola ](https://profiles.wordpress.org/nahuai/) * [ greenwebfoundation ](https://profiles.wordpress.org/greenwebfoundation/) * [ timcowlishaw ](https://profiles.wordpress.org/timcowlishaw/) * [ hanopcan ](https://profiles.wordpress.org/hanopcan/) [Translate “Carbon.txt” into your language.](https://translate.wordpress.org/projects/wp-plugins/carbon-txt) ### Interested in development? [Browse the code](https://plugins.trac.wordpress.org/browser/carbon-txt/), check out the [SVN repository](https://plugins.svn.wordpress.org/carbon-txt/), or subscribe to the [development log](https://plugins.trac.wordpress.org/log/carbon-txt/) by [RSS](https://plugins.trac.wordpress.org/log/carbon-txt/?limit=100&mode=stop_on_copy&format=rss). ## Changelog #### 0.5 * Rename the plugin to “Carbon.txt” with the `carbon-txt` slug and text domain, as required for WordPress.org hosting. * Remove the manual `load_plugin_textdomain()` call; WordPress loads translations automatically. Translations are served through translate.wordpress.org and are no longer shipped in the plugin package. * Update the “Tested up to” version to 7.1. * Validate your domain against the Green Web Foundation’s hosted validator automatically after every save — no API key or setup required, with a settings-screen toggle to turn validation off. * Remove the per-site Green Web Foundation API key field; the shared key used for validation now ships with the plugin. * Expand the documentation of the external call to the Green Web Foundation validator, in the “External services” section: what is sent, when, where, and links to its terms, privacy policy and documentation. * Look for an existing `carbon.txt` at the public document root instead of the WordPress install path, so the check also works on sites installed in a subdirectory. Other layouts can override the detected root with the `wp_carbon_txt_public_root` filter. * Stop offering the deprecated “web page” document type in the picker; new disclosures start at “sustainability page”, and existing “web page” disclosures keep working. * Mark required and optional fields in the editor, and report the entries skipped when saving because a required field was missing. * Refresh the wording across the settings screen and update the Spanish translation. #### 0.4.1 * Add an optional Green Web Foundation API key field: after each save, the plugin asks the Green Web Foundation’s hosted validator to validate your domain (publicly reachable domains only). * Support additional carbon.txt spec versions via a per-version document-type table, and add an optional `domain` field to disclosures. * Skip WordPress’s canonical redirect for `/carbon.txt` so the file isn’t redirected away from its expected path. * Offer to export your disclosures before deactivating the plugin, and collapse the settings-page backup section by default. #### 0.3.0 * Check the well-known location (`/.well-known/carbon.txt`) for an existing file, with the same import and cleanup tools already offered for the domain root. * Permanently delete an imported file once its disclosures have been saved, instead of renaming it aside. * Add a “Keep a copy” section to copy your disclosures to the clipboard or download them as a file before deactivating or deleting the plugin. * Detect a `carbon-txt-location` DNS TXT delegation record on your domain and warn that it takes priority over this plugin’s output. #### 0.2.0 * Add a media library file picker as a third way to point a disclosure at a URL, alongside pasting one or selecting a page. * Remember the selected page or file by ID, so revisiting a disclosure shows the same selection instead of falling back to a plain URL. * Detect a carbon.txt file already on the server, warn that the web server may keep serving it directly, and offer to import disclosures found in it. * Offer to rename an existing file aside as a dated backup (never deleted) once settings have been saved. #### 0.1.0 * Multiple organisational disclosures, each with a document type, a URL or page, and an optional title and valid-until date. * Live preview and /carbon.txt endpoint. * Add a Settings link on the Plugins screen and redirect to the settings page after activating the plugin on its own. ## Meta * Version **0.5** * Last updated **11 hours ago** * Active installations **Fewer than 10** * WordPress version ** 6.6 or higher ** * Tested up to **7.1.4** * PHP version ** 7.4 or higher ** * Tags * [carbon](https://wordpress.org/plugins/tags/carbon/)[carbon.txt](https://wordpress.org/plugins/tags/carbon-txt/) [emissions](https://wordpress.org/plugins/tags/emissions/)[green web](https://wordpress.org/plugins/tags/green-web/) [sustainability](https://wordpress.org/plugins/tags/sustainability/) * [Advanced View](https://wordpress.org/plugins/carbon-txt/advanced/) ## Ratings No reviews have been submitted yet. [Your review](https://wordpress.org/support/plugin/carbon-txt/reviews/#new-post) [See all reviews](https://wordpress.org/support/plugin/carbon-txt/reviews/) ## Contributors * [ Nahuai Badiola ](https://profiles.wordpress.org/nahuai/) * [ greenwebfoundation ](https://profiles.wordpress.org/greenwebfoundation/) * [ timcowlishaw ](https://profiles.wordpress.org/timcowlishaw/) * [ hanopcan ](https://profiles.wordpress.org/hanopcan/) ## Support Got something to say? Need help? [View support forum](https://wordpress.org/support/plugin/carbon-txt/)