Before you start integrating your app, determine the method required for integrating an app with an online store by verifying whether its published theme supports app blocks.

> Tip:
> If a theme doesn't currently support app blocks, and you maintain the theme or a store where the theme is used, then you can also consider [migrating the theme to support app blocks](/docs/storefronts/themes/os20#migrating-to-online-store-2-0).

## Verification criteria

To verify whether a theme supports app blocks, you need to determine the following:

* Whether the template where your app is injected supports [JSON](/docs/storefronts/themes/architecture/templates/json-templates).

* The main section in the template.

* Whether the section where your app is injected has a block of type [`@app`](/docs/storefronts/themes/architecture/blocks/app-blocks) in its schema.

For an example, refer to Shopify's sample [product reviews app](https://github.com/Shopify/product-reviews-sample-app).

To see a theme that uses JSON templates and supports app blocks in several sections, refer to Shopify's reference theme, [Dawn](/docs/storefronts/themes/tools/dawn).

## Requirements

You've requested the `read_themes` [GraphQL Admin API access scope](/docs/api/usage/access-scopes#authenticated-access-scopes).

## Verify support for app blocks

You can use the following code to verify that a theme supports app blocks. The code uses [Shopify's Node library](/docs/api#api-libraries), which provides support for JavaScript apps to access the [GraphQL Admin API](/docs/api/admin-graphql).


```js
import {shopifyApi} from '@shopify/shopify-api';

// Create library object
const shopify = shopifyApi({
  // The next four values are typically read from environment variables for added security
  apiKey: 'APIKeyFromPartnerDashboard',
  apiSecretKey: 'APISecretFromPartnerDashboard',
  scopes: ['read_products'],
  hostName: 'cloudflare-tunnel-address',
  ...
});

// Specify the name of the template that the app will integrate with
const APP_BLOCK_TEMPLATES = ["product", "collection", "index"];
const getMainThemeId = `
query getMainThemeId {
  themes(first: 1, roles: [MAIN]) {
    nodes {
      id
    }
  }
}`;

let response = await client.request(getMainThemeId);
const themeId = response.data.themes.nodes[0].id;

// Retrieve the JSON templates that we want to integrate with
const getFilesQuery = `
query getFiles($filenames: [String!]!, $themeId: ID!) {
  theme(id: $themeId) {
    files(filenames: $filenames) {
      nodes {
        filename
        body {
        ... on OnlineStoreThemeFileBodyText { content }
        ... on OnlineStoreThemeFileBodyBase64 { contentBase64 }
        }
      }
    }
  }
}
`;

response = await client.request(getFilesQuery, {
  variables: {
    themeId: themeId,
    filenames: APP_BLOCK_TEMPLATES.map((f) => `templates/${f}.json`),
  },
});

const jsonTemplateFiles = response.data.theme.files.nodes;
if (
  jsonTemplateFiles.length > 0 &&
  jsonTemplateFiles.length === APP_BLOCK_TEMPLATES.length
) {
  console.log("All desired templates support sections everywhere!");
} else if (jsonTemplateFiles.length) {
  console.log(
    "Only some of the desired templates support sections everywhere.",
  );
}
const jsonTemplateData = jsonTemplateFiles.map((file) => {
  return { filename: file.filename, body: jsonc_parse(file.body.content) };
});

// Retrieve the body of JSON templates and find what section is set as `main`
const templateMainSections = jsonTemplateData
  .map((file) => {
    const main = Object.entries(file.body.sections).find(
      ([id, section]) => id === "main" || section.type.startsWith("main-"),
    );
    if (main) {
      return "sections/" + main[1].type + ".liquid";
    }
  })
  .filter((section) => section);

const sectionFiles = await client.request(getFilesQuery, {
  variables: { themeId: themeId, filenames: templateMainSections },
});

const sectionsWithAppBlock = sectionFiles.data.theme.files.nodes
  .map((file) => {
    let acceptsAppBlock = false;
    const match = file.body.content.match(
      /\{\%\s+schema\s+\%\}([\s\S]*?)\{\%\s+endschema\s+\%\}/m,
    );
    const schema = jsonc_parse(match[1]);
    if (schema && schema.blocks) {
      acceptsAppBlock = schema.blocks.some((b) => b.type === "@app");
    }
    return acceptsAppBlock ? file : null;
  })
  .filter((section) => section);

if (
  jsonTemplateData.length > 0 &&
  jsonTemplateData.length === sectionsWithAppBlock.length
) {
  console.log(
    "All desired templates have main sections that support app blocks!",
  );
} else if (sectionsWithAppBlock.length) {
  console.log("Only some of the desired templates support app blocks.");
} else {
  console.log("None of the desired templates support app blocks");
}
```



## Specify the method for integrating the app

<table>
  <caption>App integration methods</caption>
  <tr>
    <th scope="col">App block support</th>
    <th scope="col">Integration method</th>
  </tr>
  <tr>
    <td>Yes</td>
    <td>Skip requests made to the <code><a href="/docs/api/admin-graphql/latest/objects/ScriptTag">ScriptTag</a></code> object.
    </td>
  </tr>
  <tr>
    <td>No</td>
    <td><p>Make requests to the <code><a href="/docs/api/admin-graphql/latest/objects/ScriptTag">ScriptTag</a></code> object, or provide instructions to add code using a <a href="https://help.shopify.com/manual/online-store/themes/theme-structure/extend#add-custom-html-or-liquid">custom Liquid</a> section or block, or the <a href="https://help.shopify.com/manual/online-store/themes/theme-structure/extend/add-css">custom CSS</a> setting.</p>
    </td>
  </tr>
</table>

## Provide onboarding instructions

You need to provide merchants with post-installation instructions about onboarding your app.

To learn more about writing effective help documentation, refer to [Help documentation](https://polaris.shopify.com/content/help-documentation) in Shopify Polaris and to the theme app extension [onboarding instruction guidelines](/docs/apps/build/online-store/theme-app-extensions/ux#merchant-onboarding).

<table>
  <caption>App block support and onboarding instruction examples</caption>
  <tr>
    <th scope="col">App block support</th>
    <th scope="col">Onboarding</th>
  </tr>
  <tr>
    <td>Yes</td>
    <td><p>Provide merchants with instructions about using the app block.</p>
    <p>For example, document instructions for adding the app block to the theme.</p></td>
  </tr>
  <tr>
    <td>No
    <td><p>Provide merchants with instructions about any configurations required to integrate the app.</p>
    <p>For example, document instructions for copying and pasting a code snippet to a page.</p></td>
  </tr>
</table>