IsTempMail
Block Disposable Email API
About
IsTempMail is a real-time API that detects disposable, temporary, and throwaway email addresses at signup — so you can block fake users before they reach your database. It's backed by a 130,000+ domain blocklist updated multiple times daily, and returns clear blocked and unresolvable fields you can act on instantly.
Control AI spend
Stop abusers from minting trial accounts that burn GPU minutes, API credits, and generation quotas
Stop free-trial abuse
Keep paid features paid; protect unit economics
Protect deliverability
Fewer bounces, better sender reputation
Clean metrics
Honest activation, conversion, and retention numbers
Cut fraud signals
Block fake signups before they pollute your funnel
Trusted by traditional SaaS and AI-native teams alike. We power Botpress, Chatfuel, Lovo, and many others. Also ships as a WordPress plugin (free + premium) with form-level rules, plus bulk checking, personal block/allow lists, and domain reporting.
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FounderPlaybooks.
What other founders did to grow.
2722 dispatches from hundreds of founders, pulled from the week's best podcasts.
We correlated the number of cheers received to workout completions and long-term retention and so we realize the importance of this feature and people feeling like there are others that are doing it with them... we now use that to figure out how do we incentivize and increase the number of outbound cheers.
Social Cheers Feature Correlates Directly With Workout Completions and Long-Term Retention
Ladder discovered that users who receive cheers from other members during workouts are significantly more likely to complete the workout and retain long-term. The mechanism is social accountability and belonging. Once identified, the team engineered an early-trial cheers boost — new users now receive more inbound cheers in their first days — to create the psychological connection before it forms naturally.
Teams create product soul. You can't vibe code a brand. People want to connect with the apps that they use — they want to feel something. A recipe for failure is just to create something that has a function, which AI does really really well. You need more than that to be successful.
You can't vibe-code a brand — teams create product soul, and soul is what users actually connect with
Schlenker's contrarian take on the 'billion-dollar one-person company' narrative: AI enables fast function creation, but function alone does not create the emotional connection that drives long-term retention and brand loyalty. Opal's brand — the gemstone visual metaphor, the opal-calm-mind etymology, the 'scrolling kills' campaign, the crack-the-gemstone reward interaction — required deliberate human craft. Competitors can copy features; they cannot copy accumulated taste. As AI lowers the cost of building app functions, brand and soul become the differentiator that cannot be commoditized.
There's a play for whatever you're stuck on.
Read all 2722 playbooks
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