I started a weekly newsletter called Sparkspec. Each week I read public threads on Hacker News, Reddit and X, keep complaints that are specific and repeated, and turn three of them into small apps you could build in a day. Here are the three ideas from Issue 1. Each links to the thread it came from, so you can read the original words yourself.
A note up front: a complaint showing up in public is a signal, not proof of demand or revenue. Talk to the people in the thread before you invest heavily.
1. Hangar: one file that knows where all your side projects live
The problem. Solo builders ship lots of small projects across lots of hosts. Months later they cannot say what runs where, what is still up, or which domains are about to renew for abandoned projects. A builder on r/SideProject describes having eight or nine side projects spread across different platforms, with a tracking spreadsheet that is always out of date. In an Ask HN thread on unfinished projects, people describe "a graveyard of expired domains."
The idea. A single hangar.yaml in git listing projects and domains. A hangar check command pings each health URL, and domain expiry comes from public RDAP, so no registrar API keys are needed. A local dashboard shows what is up, what renews soon, and highlights domains renewing on projects you marked as abandoned.
Stack suggestion. Bun, TypeScript, SQLite for check history, Hono for a localhost dashboard.
2. Tripwire: a circuit breaker for agents that will not stop retrying
The problem. An Ask HN post asks how people keep AI coding agents from burning money. The author writes that their agents "retry a bit more than it should," and that everything "shows up as aggregate usage." Provider dashboards show totals, not which agent or task caused the spike.
The idea. A small local proxy for OpenAI-compatible APIs that tags requests per agent and task, detects a task sending near-identical requests in a loop, and trips a breaker before the bill grows. Existing gateways offer budgets, but loop detection is the narrow gap.
3. Linkroll: a growing list of links, on files you own
The problem. Another Ask HN thread asks how to share a growing list of URLs with friends, "like del.icio.us in the old days." Platforms and paid apps are the usual answers, and full bookmark managers like Karakeep already cover a lot of it.
The idea. The smallest possible version: no database, no server. Links live as files in a git repo, which build to a static site and an RSS feed that people can follow. It is for people who would rather publish from their own repo than rent a feed.
Where the full specs are
Each idea in the newsletter has a one-page spec (who it is for, features, out of scope, data model, a one day build plan) and a prompt you can paste into Cursor, Claude Code, Bolt or Lovable. Issue 1 is fully open, so you can read all three with no signup:
If you want one issue like this in your inbox each week, you can subscribe at https://sparkspec.co. It is free. I would also like to hear which of these you would actually use, and which complaint you keep seeing that I should look at next.
Top comments (1)
I like that you put the "a complaint is a signal, not proof" note up front, a lot of idea newsletters skip it. The Hangar idea hits close to home: the domain-renewal part alone is something people would pay a little for, because forgetting one is the moment the pain becomes real money. Linking each idea back to the original thread is a nice touch too, it makes the ideas checkable.