You can post your jobs to Indeed and other job boards owned by Indeed (including Simplyhired) using Recruiterflow.
Note: You can only opt-out of Indeed integration at global level and not at job level. All the jobs on your careers page, need to be published on Indeed if the integration is on.
Integrating Indeed with Recruiterflow
Go to Settings and then General Settings.
Check on 'Enable Indeed and SimplyHired job posting
Enter your email address which Indeed can verify for an authentic job posting, hit Save and you are done!