fix: handle empty notification recipients

[SahilJat]

Thanks for submitting a PR! Please check the boxex below:

• I have read the Contributing
  Guide.

• I have added information to docs/ if required
  so people know about the feature.

• I have filled in the "Changes" section below.

• I have filled in the "How did you test this
  code" section below.

  Changes

  Closes Sendgrid API calls raising HTTP 400 Bad Requests #7353
  This PR resolves an issue where the background tasks for sending API usage and flag blocked notifications crash with a BadRequestsError: HTTP Error 400: Bad Request.

  This occurs when using external API-based email
  backends (like SendGrid or AWS SES) and the
  organisation has no valid recipients (e.g., zero
  total users, or no admin users when the usage
  threshold is <100%). Unlike traditional SMTP
  backends, API backends strictly validate the payload and return a 400 error if the recipient_list is empty.
  Changes made:

• Added an early return guard checking if not recipient_emails: in _send_api_usage_notification.

• Added the same early return guard in
  send_api_flags_blocked_notification to prevent the same crash there.

• Logs a warning (notification.no_recipients)
  instead of attempting to send the email.

How did you test this code?

• Added a new unit test: test_handle_api_usage_notifications__no_admin_users_ _skips_notification to explicitly verify that the
  notification is safely skipped and no 400 error is thrown when an organisation has no users.
• Ran existing unit tests for organisations_tasks
  to ensure no regressions.

[vercel]

@SahilJat is attempting to deploy a commit to the Flagsmith Team on Vercel.

A member of the Team first needs to authorize it.

[gemini-code-assist]

Code Review

This pull request introduces checks to handle cases where no recipient emails are found for API usage and blocked notifications, including a new unit test for this scenario. Feedback suggests that returning early without creating a notification record will lead to redundant processing and log noise in subsequent task runs, as the organization will be re-evaluated every 12 hours.

[Zaimwa9]

@SahilJat thanks for your contribution. You'll need to run make lint or generate-docs to regenerate the events catalogue as you created 2 new ones

[SahilJat]

Hi @Zaimwa9 i did run make lint and it shows around 22k lines edited , is this fine?

[Zaimwa9]

Sorry, I should have been more specific as the command should be run from api/, it edited all the docs it seems

[SahilJat]

hi @Zaimwa9 thanks for the hint , i did the changes required now, please have a look and let me know.

[Zaimwa9]

Tests need an update 👍

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.35%. Comparing base (2e16ede) to head (5a1373e).
⚠️ Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7589      +/-   ##
==========================================
- Coverage   98.50%   98.35%   -0.16%     
==========================================
  Files        1430     1436       +6     
  Lines       54254    54274      +20     
==========================================
- Hits        53444    53382      -62     
- Misses        810      892      +82     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[SahilJat]

Hi @Zaimwa9 all the test cases are passing and test coverage is covered too. Thanks

[Zaimwa9]

Sorry for the back and forth. Gemini comment is worth addressing

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
docs	Ready	Preview, Comment	May 28, 2026 8:10am

2 Skipped Deployments

Project	Deployment	Actions	Updated (UTC)
flagsmith-frontend-preview	Ignored	Preview	May 28, 2026 8:10am
flagsmith-frontend-staging	Ignored	Preview	May 28, 2026 8:10am