(1/2) Implement store/caching for attachments

[NJ-2020]

Explanation of Change

Original PR: #63723

This PR adds functionality to store and cache attachment files and markdown attachment, currently it only supports images file types

Note: image preview in offline mode will be implemented in PR (2/2).

We use CacheAPI for web and filesystem for native platforms to manage attachment storage.

Each attachment has a unique ID (attachment_id / data-attachment-id) for storing and previewing files on both web and native

For new attachments, we use the data-attachment-id parameter, for older attachments which doesn't have this parameter, we combine the reportActionID with the attachment's index in the selection list:

Single attachment: reportActionID_0
Multiple attachments (inside on action/message/comment) reportActionID_0, reportActionID_1, etc

Fixed Issues

$ #9402
PROPOSAL: #9402 (comment)

Tests

Observing changes

Web:

1. Open inspect element
2. Go to > Applications tab
   OnyxDB:
3. Go to > Storage > IndexedDB > OnyxDB > keyvaluepairs
4. Click 🔄 to reload the lists
5. Click the input search bar, and search for attachment key i.e attachment_...
   Cache API
6. Go to Storage > Cache storage > attachments
7. See attachment lists

Screen.Recording.2025-08-21.at.13.24.41.mov

Native:

• Android:

1. Go to your Media/Files
2. Search for com.expensify.chat.dev or similar, usally it's located under root/android/data/com.expensify.chat.dev
3. Look for the files folder or related folders like Documents/DCIM > attachments, then check for any new attachment files. For better results, try filtering by images only.

• IOS:

Note: I don't have IOS physical device, so it might be similar to emulator device

1. Go to Files
2. Search for New Expensify or similar
3. Open that app/folder > attachments folder, lookup for new attachment file

For more details can been seen in the attached recording videos below

Test cases:

Upload attachment file

1. Open the App
2. Go to any chat
3. Upload a single or multiple attachment files
4. [Observe the changes]

Markdown image attachment

1. Open the App
2. Go to any chat
3. Click the composer and type any single or multiple markdown image url i.e ![](https://images.unsplash.com/photo-1726066012751-2adfb5485977?w=100)
4. [Observe the changes]

Delete markdown/attachment

1. Open the App
2. Go to any chat
3. Delete any markdown attachment or any attachment file
4. [Observe the changes] - ensure the selected attachment are deleted from Onyx, CacheAPI and [device storage] for Native

Clear Attachments on Logout

1. Open the app with an account logged in + cached attachments
2. Logout
3. [Observe the changes] - ensure all attachments are deleted from Onyx, CacheAPI, and [device storage] for Native

Opening/navigating attachments

1. Open the app
2. Go to any chat
3. Verify that: Opening and navigating between attachments still works as expected

Offline tests

Same as tests, for markdown attachment it will requires internet connection

QA Steps

• Verify that no errors appear in the JS console

Same as tests

PR Author Checklist

• I linked the correct issue in the ### Fixed Issues section above
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I added steps for the expected offline behavior in the Offline steps section
  • I added steps for Staging and/or Production testing in the QA steps section
  • I added steps to cover failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
  • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
• I included screenshots or videos for tests on all platforms
• I ran the tests on all platforms & verified they passed on:
  • Android: Native
  • Android: mWeb Chrome
  • iOS: Native
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
  • MacOS: Desktop
• I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
• I verified there are no new alerts related to the canBeMissing param for useOnyx
• I followed proper code patterns (see Reviewing the code)
  • I verified that any callback methods that were added or modified are named for what the method does and never what callback they handle (i.e. toggleReport and not onIconClick)
  • I verified that comments were added to code that is not self explanatory
  • I verified that any new or modified comments were clear, correct English, and explained "why" the code was doing something instead of only explaining "what" the code was doing.
  • I verified any copy / text shown in the product is localized by adding it to src/languages/* files and using the translation method
    • If any non-english text was added/modified, I used JaimeGPT to get English > Spanish translation. I then posted it in #expensify-open-source and it was approved by an internal Expensify engineer. Link to Slack message:
  • I verified all numbers, amounts, dates and phone numbers shown in the product are using the localization methods
  • I verified any copy / text that was added to the app is grammatically correct in English. It adheres to proper capitalization guidelines (note: only the first word of header/labels should be capitalized), and is either coming verbatim from figma or has been approved by marketing (in order to get marketing approval, ask the Bug Zero team member to add the Waiting for copy label to the issue)
  • I verified proper file naming conventions were followed for any new files or renamed files. All non-platform specific files are named after what they export and are not named "index.js". All platform-specific files are named for the platform the code supports as outlined in the README.
  • I verified the JSDocs style guidelines (in STYLE.md) were followed
• If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
• I followed the guidelines as stated in the Review Guidelines
• I tested other components that can be impacted by my changes (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar are working as expected)
• I verified all code is DRY (the PR doesn't include any logic written more than once, with the exception of tests)
• I verified any variables that can be defined as constants (ie. in CONST.ts or at the top of the file that uses the constant) are defined as such
• I verified that if a function's arguments changed that all usages have also been updated correctly
• If any new file was added I verified that:
  • The file has a description of what it does and/or why is needed at the top of the file if the code is not self explanatory
• If a new CSS style is added I verified that:
  • A similar style doesn't already exist
  • The style can't be created with an existing StyleUtils function (i.e. StyleUtils.getBackgroundAndBorderStyle(theme.componentBG))
• If new assets were added or existing ones were modified, I verified that:
  • The assets are optimized and compressed (for SVG files, run npm run compress-svg)
  • The assets load correctly across all supported platforms.
• If the PR modifies code that runs when editing or sending messages, I tested and verified there is no unexpected behavior for all supported markdown - URLs, single line code, code blocks, quotes, headings, bold, strikethrough, and italic.
• If the PR modifies a generic component, I tested and verified that those changes do not break usages of that component in the rest of the App (i.e. if a shared library or component like Avatar is modified, I verified that Avatar is working as expected in all cases)
• If the PR modifies a component related to any of the existing Storybook stories, I tested and verified all stories for that component are still working as expected.
• If the PR modifies a component or page that can be accessed by a direct deeplink, I verified that the code functions as expected when the deeplink is used - from a logged in and logged out account.
• If the PR modifies the UI (e.g. new buttons, new UI components, changing the padding/spacing/sizing, moving components, etc) or modifies the form input styles:
  • I verified that all the inputs inside a form are aligned with each other.
  • I added Design label and/or tagged @Expensify/design so the design team can review the changes.
• If a new page is added, I verified it's using the ScrollView component to make it scrollable when more elements are added to the page.
• I added unit tests for any new feature or bug fix in this PR to help automatically prevent regressions in this user flow.
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.

Screenshots/Videos

Android: Native

Upload attachment file

9402_android_native_attachment_file.mp4

Markdown attachment

9402_android_native_markdown_attachment.mp4

Delete attachment

9402_android_native_delete_attachment.mp4

Update attachment

9402_android_native_update_attachment.mp4

Android: mWeb Chrome

Upload attachment file

9402_android_mweb_attachment_file.mp4

Markdown image attachment

9402_android_mweb_markdown_image.mov

Delete attachment

9402_android_mweb_delete_attachment.mov

Update attachment

9402_android_mweb_update_attachment.mp4

iOS: Native

Upload attachment file

9402_ios_native_attachment_file.mp4

Markdown attachment

9402_ios_native_markdown_attachment.mov

Delete attachment

9402_ios_native_delete_attachment.mov

Update attachment

9402_ios_native_update_attachment.mp4

iOS: mWeb Safari

Upload attachment file

9402_ios_mweb_attachment_file.mov

Markdown image attachment

9402_ios_mweb_markdown_image.mov

Delete attachment

9402_ios_mweb_delete_attachment.mov

Update attachment

9402_ios_mweb_update_attachment.mov

MacOS: Chrome / Safari

Upload attachment file

9402_web_attachment_file.mov

Markdown image attachment

9402_web_markdown_image.mov

Delete attachment

9402_web_delete_attachment.mp4

Update attachment

9402_web_update_attachment.mp4

MacOS: Desktop

Upload attachment file

9402_desktop_attachment_file.mov

Markdown image attachment

9402_desktop_markdown_image.mov

Delete attachment

9402_desktop_delete_attachment.mov

Update attachment

9402_desktop_update_attachment.mov

Feedback resolved

[Julesssss]

LGTM. Just awaiting final approval from @parasharrajat and we're good to go!

[parasharrajat]

Screenshots

🔲 iOS / native

16.03.2026_16.48.57_REC.mp4

🔲 iOS / Safari

16.03.2026_16.51.04_REC.mp4

🔲 MacOS / Chrome

16.03.2026_16.24.13_REC.mp4

🔲 Android / native

16.03.2026_16.45.55_REC.mp4

16.03.2026_16.54.15_REC.mp4

[parasharrajat]

Reviewer Checklist

• I have verified the author checklist is complete (all boxes are checked off).
• I verified the correct issue is linked in the ### Fixed Issues section above
• I verified testing steps are clear and they cover the changes made in this PR
  • I verified the steps for local testing are in the Tests section
  • I verified the steps for Staging and/or Production testing are in the QA steps section
  • I verified the steps cover any possible failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
• I checked that screenshots or videos are included for tests on all platforms
• I included screenshots or videos for tests on all platforms
• I verified that the composer does not automatically focus or open the keyboard on mobile unless explicitly intended. This includes checking that returning the app from the background does not unexpectedly open the keyboard.
• I verified tests pass on all platforms & I tested again on:
  • Android: HybridApp
  • Android: mWeb Chrome
  • iOS: HybridApp
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
• If there are any errors in the console that are unrelated to this PR, I either fixed them (preferred) or linked to where I reported them in Slack
• I verified proper code patterns were followed (see Reviewing the code)
  • I verified that any callback methods that were added or modified are named for what the method does and never what callback they handle (i.e. toggleReport and not onIconClick).
  • I verified that comments were added to code that is not self explanatory
  • I verified that any new or modified comments were clear, correct English, and explained "why" the code was doing something instead of only explaining "what" the code was doing.
  • I verified any copy / text shown in the product is localized by adding it to src/languages/* files and using the translation method
  • I verified all numbers, amounts, dates and phone numbers shown in the product are using the localization methods
  • I verified any copy / text that was added to the app is grammatically correct in English. It adheres to proper capitalization guidelines (note: only the first word of header/labels should be capitalized), and is either coming verbatim from figma or has been approved by marketing (in order to get marketing approval, ask the Bug Zero team member to add the Waiting for copy label to the issue)
  • I verified proper file naming conventions were followed for any new files or renamed files. All non-platform specific files are named after what they export and are not named "index.js". All platform-specific files are named for the platform the code supports as outlined in the README.
  • I verified the JSDocs style guidelines (in STYLE.md) were followed
• If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
• I verified that this PR follows the guidelines as stated in the Review Guidelines
• I verified other components that can be impacted by these changes have been tested, and I retested again (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar have been tested & I retested again)
• I verified all code is DRY (the PR doesn't include any logic written more than once, with the exception of tests)
• I verified any variables that can be defined as constants (ie. in CONST.ts or at the top of the file that uses the constant) are defined as such
• If a new component is created I verified that:
  • A similar component doesn't exist in the codebase
  • All props are defined accurately and each prop has a /** comment above it */
  • The file is named correctly
  • The component has a clear name that is non-ambiguous and the purpose of the component can be inferred from the name alone
  • The only data being stored in the state is data necessary for rendering and nothing else
  • For Class Components, any internal methods passed to components event handlers are bound to this properly so there are no scoping issues (i.e. for onClick={this.submit} the method this.submit should be bound to this in the constructor)
  • Any internal methods bound to this are necessary to be bound (i.e. avoid this.submit = this.submit.bind(this); if this.submit is never passed to a component event handler like onClick)
  • All JSX used for rendering exists in the render method
  • The component has the minimum amount of code necessary for its purpose, and it is broken down into smaller components in order to separate concerns and functions
• If any new file was added I verified that:
  • The file has a description of what it does and/or why is needed at the top of the file if the code is not self explanatory
• If a new CSS style is added I verified that:
  • A similar style doesn't already exist
  • The style can't be created with an existing StyleUtils function (i.e. StyleUtils.getBackgroundAndBorderStyle(theme.componentBG)
• If the PR modifies code that runs when editing or sending messages, I tested and verified there is no unexpected behavior for all supported markdown - URLs, single line code, code blocks, quotes, headings, bold, strikethrough, and italic.
• If the PR modifies a generic component, I tested and verified that those changes do not break usages of that component in the rest of the App (i.e. if a shared library or component like Avatar is modified, I verified that Avatar is working as expected in all cases)
• If the PR modifies a component related to any of the existing Storybook stories, I tested and verified all stories for that component are still working as expected.
• If the PR modifies a component or page that can be accessed by a direct deeplink, I verified that the code functions as expected when the deeplink is used - from a logged in and logged out account.
• If the PR modifies the UI (e.g. new buttons, new UI components, changing the padding/spacing/sizing, moving components, etc) or modifies the form input styles:
  • I verified that all the inputs inside a form are aligned with each other.
  • I added Design label and/or tagged @Expensify/design so the design team can review the changes.
• If a new page is added, I verified it's using the ScrollView component to make it scrollable when more elements are added to the page.
• For any bug fix or new feature in this PR, I verified that sufficient unit tests are included to prevent regressions in this flow.
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.
• I have checked off every checkbox in the PR reviewer checklist, including those that don't apply to this PR.

🎀 👀 🎀 C+ reviewed

[parasharrajat]

Didn't see any issues? Main testing will be done in next PR where we will integrate this feature to the App.

[parasharrajat]

@NJ-2020 Can you add non technical steps for QA steps?

[NJ-2020]

@NJ-2020 Can you add non technical steps for QA steps?

Done

[Julesssss]

currently it only supports images file types

Nice work @NJ-2020 @parasharrajat, thanks for finishing this one up. 🎉

[Julesssss]

For anyone coming here from a deploy blocker, we will help you resolve issues. Please don't revert.

[github-actions]

🚧 @Julesssss has triggered a test Expensify/App build. You can view the workflow run here.

[OSBotify]

✋ This PR was not deployed to staging yet because QA is ongoing. It will be automatically deployed to staging after the next production release.

[github-actions]

🧪🧪 Use the links below to test this adhoc build on Android, iOS, and Web. Happy testing! 🧪🧪
Built from App PR #65321.

Android 🤖	iOS 🍎
https://ad-hoc-expensify-cash.s3.us-east-1.amazonaws.com/rock-artifacts/ad-hoc/rock-android-Adhoc-1c65fa5-03346cd-6e767c9c7e5e45305f3fabe687886df6dead7db1/index.html	https://ad-hoc-expensify-cash.s3.us-east-1.amazonaws.com/rock-artifacts/ad-hoc/rock-ios-device-AdHoc-1c65fa5-03346cd-17cb72b46ff698009f95e6deec623d99527dd40a/index.html

Web 🕸️
https://65321.pr-testing.expensify.com

---

👀 View the workflow run that generated this build 👀

[OSBotify]

🚀 Deployed to staging by https://github.com/Julesssss in version: 9.3.39-0 🚀

platform	result
🕸 web 🕸	success ✅
🤖 android 🤖	success ✅
🍎 iOS 🍎	success ✅

[nlemma]

@NJ-2020 this PR is failing due to #85557

[vincdargento]

Deploy Blocker #85604 was identified to be related to this PR.

[OSBotify]

🚀 Deployed to production by https://github.com/cristipaval in version: 9.3.39-3 🚀

platform	result
🕸 web 🕸	success ✅
🤖 android 🤖	failure ❌
🍎 iOS 🍎	success ✅

[Julesssss]

Above issues demoted from blocker status