Show HN: Spikelog – A simple metrics service for scripts, cron jobs, and MVPs (spikelog.com)

I built Spikelog because I kept wanting to track simple numbers over time but every time I looked at proper observability tools, I'd bounce off the setup complexity. I wanted to make something that didn't require a lot of thinking to use.

Spikelog is made to be as simple as possible:

- POST a JSON with chart name + value (you can add some tags as well but I've not tested this part works yet)

- Chart appears automatically

- 1,000 point rolling window per chart (old data expires, no retention config)

- Max 10 charts

That's basically the whole product.

I built it in about a day using Cursor. The API is intentionally minimal so AI assistants can use it too.

I have a prompt that lets your coding agent analyze a codebase and add tracking automatically (after you approve the plan).

I used it to make Spikelog track itself: https://spikelog.com/p/spikelog

There's no alerting yet (that's next), no complex aggregations, no dashboards beyond the auto-generated charts. If you need real observability use something fully featured like Axiom or Datadog. This is for people who just want to see if a number went up or down and don't want to build that themselves. i.e. they want something slightly better than just logging the number.

You can also share the charts publicly and I might add some password protection if there is demand for that.

I haven't battle-tested it under heavy load. The rolling window deletion is naive (deletes oldest points on insert). There are probably edge cases I haven't hit yet.

Would love feedback, especially if you try it and hit something broken.