If you managing multiple sites in your portfolio, you will understand the challenge to manage the indexing level of your seo pages.

I have explore the possibility using API to check and submit indexing pages - but the problem is limit of 200 submission per day - if you want to submit 1000's of pages per day - you will need multiple google accounts.

URL monitor did what I need - automated monitoring and submit index.

I submitted a site 2 days back - already have 40+ pages indexed due to the process.

I would suggest few features to be added though:
1. API access for us to manually submit page to be index urgently
2. Increase limit of pages that can be manually added (currently 100) - I would prefer in 500 or even 1000