Blindspot
Check your English writing with AI, understand grammar mistakes, and practice the rules you struggle with.
AI & Machine Learning·Productivity·Education
About
Blindspot is an AI-powered English writing checker designed to help learners understand their mistakes, learn through their own writing, and turn weak spots into personalized practice. It finds grammar and vocabulary errors, explains the underlying rules, and provides targeted exercises to help users improve.
The platform is built for individuals looking to enhance their English writing skills by analyzing real texts such as emails, messages, work notes, and journal entries. Users can save vocabulary words to a personal dictionary, explore collocations and synonyms, and practice with tailored flashcards and quizzes.
What sets Blindspot apart is its focus on personalized learning derived directly from the user's own writing patterns rather than generic exercises. It offers a transparent, interactive approach to language learning starting with free text checks and no credit card required.
Ready to launch?
Submit your product and get discovered by builders and creators worldwide.
Launch Now
FounderPlaybooks.
What other founders did to grow.
2722 dispatches from hundreds of founders, pulled from the week's best podcasts.
We experimented to some users actually the threshold was three times a day and then if you try to allow them to watch it more frequently then the retention drops but actually one to three times actually retention and engagement improved it's completely counterintuitive.
Rewarded Video Improved Retention — But Only Up to 3 Times Per Day
Anton's team found that adding rewarded video ads (earn 1 sweatcoin per video, optional) improved retention for about 20% of users — but only when capped at 1-3 views per day. Above that threshold, the effect reversed. This maps directly to gaming industry knowledge around rewarded video mechanics, where the reward loop adds value until it becomes noise. The lesson for non-gaming apps: the right monetization can actually improve engagement metrics, but dosage matters more than availability.
I spend 1 hour a day marketing I post the videos same day I usually don't schedule them far out just because I can iterate way faster... I run three Instagram accounts to split up my videos because I want to try and spread all of them out by at least 3 or 4 hours I don't want the algorithm to think I'm spamming it.
Post Same-Day Instead Of Batching So You Can Iterate On Winning Formats In Real Time
Jack refuses to batch a month of content because daily posting lets him iterate on what's working that week instead of locking in a dead template. He splits volume across 3 IG accounts with 3-4 hour gaps and never reuses the same video+metadata, since modern algorithms now detect duplicate uploads.
There's a play for whatever you're stuck on.
Read all 2722 playbooks