module.exports = {
  plugins: [
      resolve: 'gatsby-plugin-robots-txt',
      options: {
        host: 'https://www.example.com',
        sitemap: 'https://www.example.com/sitemap.xml',
        env: {
          development: {
            policy: [{userAgent: '*', disallow: ['/']}]
          production: {
            policy: [{userAgent: '*', allow: '/'}]
The env key will be taken from process.env.GATSBY_ACTIVE_ENV first (
see Gatsby Environment Variables for more information on this
variable), falling back to process.env.NODE_ENV. When this is not available then it defaults to development.
You can resolve the env key by using resolveEnv function:
gatsby-config.js
module.exports = {
  plugins: [
      resolve: 'gatsby-plugin-robots-txt',
      options: {
        host: 'https://www.example.com',
        sitemap: 'https://www.example.com/sitemap.xml',
        resolveEnv: () => process.env.GATSBY_ENV,
        env: {
          development: {
            policy: [{userAgent: '*', disallow: ['/']}]
          production: {
            policy: [{userAgent: '*', allow: '/'}]
configFile-option
You can use the configFile option to set specific external configuration:
gatsby-config.js
module.exports = {
  plugins: [
      resolve: 'gatsby-plugin-robots-txt',
      options: {
        configFile: 'robots-txt.config.js'
robots-txt.config.js
module.exports = {
  host: 'https://www.example.com',
  sitemap: 'https://www.example.com/sitemap.xml',
  policy: [{userAgent: '*'}]
Netlify
If you would like to disable crawlers
for deploy-previews you can use the
following snippet:
gatsby-config.js
const {
  NODE_ENV,
  URL: NETLIFY_SITE_URL = 'https://www.example.com',
  DEPLOY_PRIME_URL: NETLIFY_DEPLOY_URL = NETLIFY_SITE_URL,
  CONTEXT: NETLIFY_ENV = NODE_ENV
} = process.env;
const isNetlifyProduction = NETLIFY_ENV === 'production';
const siteUrl = isNetlifyProduction ? NETLIFY_SITE_URL : NETLIFY_DEPLOY_URL;
module.exports = {
  siteMetadata: {
    siteUrl
  plugins: [
      resolve: 'gatsby-plugin-robots-txt',
      options: {
        resolveEnv: () => NETLIFY_ENV,
        env: {
          production: {
            policy: [{userAgent: '*'}]
          'branch-deploy': {
            policy: [{userAgent: '*', disallow: ['/']}],
            sitemap: null,
            host: null
          'deploy-preview': {
            policy: [{userAgent: '*', disallow: ['/']}],
            sitemap: null,
            host: null
query-option
By default the site URL will come from the Gatsby node site.siteMeta.siteUrl. Like
in Gatsby’s sitemap plugin an optional GraphQL query can be
used to provide a different value from another data source as long as it returns the same shape:
gatsby-config.js
module.exports = {
  plugins: [
      resolve: 'gatsby-plugin-robots-txt',
      options: {
        query: `{
          site: MyCustomDataSource {
            siteMetadata {
              siteUrl