Hi all 
I used Mantle, and since it’s shutting down I built my own self-hosted replacement. It’s called SlotDock, and it’s open source (MIT).
GitHub - WebX47/SlotDock-oss · GitHub
It covers a lot more than reports:
Customers: every install across your apps, with plans, subscriptions and notes
Plans and billing: feature flags, limits, and billing that runs through your own app
14 reports: MRR, churn, retention, trials, funnel and more, with CSV export
Web vitals: real-merchant performance measured against Built for Shopify thresholds
Reviews: App Store reviews matched to shops
Client library: a small slotdockpackage to plug into your apps
Migration: a Mantle export/import tool so you can bring your data over
Self-hosted: your keys and data stay on your server. No access tokens or app client secret save needed.
The goal is to give other devs a head start on their own version. Fork it and shape it however you need. You can read the docs, or point an AI at the repo to get up to speed quickly.
It’s in beta and a personal project, so review it for your use case before trusting it with billing. Hope it helps anyone who was planning to build something like this, or who doesn’t want to hand their data to another third-party tool 
