Show HN: MantleDB – Anonymous JSON storage for your side projects
moonwizard Tuesday, February 24, 2026For years, I’ve been building small apps and prototypes that needed persistent cloud data, but I couldn't be bothered to set up a full database, manage an ORM, or deal with auth. Most of the projects were just too small to justify the overhead.
So I built MantleDB. It’s a simple JSON storage server designed for speed and zero-friction. There is no UI—even registration is handled via the API.
Get started instantly:
curl -s https://mantledb.sh/api/auth/register
You’ll get an AID (Admin ID) for reads/writes and an RID (Read ID) for public-facing reads.
Write to a bucket. Note: Buckets are created on write.
curl -X POST https://mantledb.sh/api/b/YOUR_AID/<bucketname> -d '{"score": 42}'
Read the data back:
curl https://mantledb.sh/api/b/YOUR_RID/<bucketname>
How it works:
Ephemeral by default: To keep things lean, a "scavenger" cron runs daily. On the free tier, buckets with no activity for 72 hours are deleted. Accounts with no buckets are cleared after one week.
Pro Plan: Removes the scavenger, increases bucket limits, and adds atomic operations (Increment, Append, etc.).
Tech Stack: Node.js + SQLite (running on AWS Lightsail).
If the free tier feels too tight or the Pro version feels too pricey, let me know! I’m happy to hand out discount codes or adjust things based on feedback.
I’m mostly looking for people to try and break it or tell me what features would make this their go-to for the next weekend hackathon.