Show HN: LogLens, a fast alternative to grep – jq for structured logs

1 points by Caelrith 17 hours ago

Hi HN, I'm the creator of LogLens.

Like many of you, I spend a lot of time digging through massive structured (mostly JSON) log files. I've always relied on grep for its speed and then piped to jq for the actual filtering, but I find this workflow gets slow and complicated, especially with multi-GB files or complex queries.

LogLens is my attempt to fix this. It's a single, fast CLI tool written in Rust that's designed specifically for structured logs. It combines a simple SQL-like query language (e.g., loglens query './logs' 'level == "error" && status >= 500') with parallel, memory-mapped file processing to be significantly faster than grep | jq.

The Model (Please Read):

This is a closed-source, freemium tool.

    Free Tier: The core features (search, query, fields, compress/decompress) are free to use, forever. My goal is for the free tier to be genuinely useful on its own.

    Pro Tier: The advanced features (tui, stats, watch, count, etc.) are part of a Pro license.

I'm a solo developer, and I'm trying to build a sustainable side income from this. The license is $79 for a year of updates, which includes a perpetual fallback license. This means that after your year is up, you can keep using the last version you downloaded, forever.

The Tech: It's written in Rust, using rayon for parallel processing and memmap2 for fast file access. The query engine is a simple, hand-written recursive parser.

I'd be grateful for any feedback you have on the tool, the query language, or the business model.

    Website (with demo GIF): https://www.getloglens.com

    Docs: https://www.getloglens.com/docs

Thanks for checking it out!

ifh-hn 12 hours ago

Good effort on creating your own application. I'm not sure I would use it pay for it just on speed alone when you consider the free alternatives, especially if you consider things like nushell. Not a criticism, just honest feedback.

Caelrith 11 hours ago

That's a totally fair point, thanks for the honest feedback.
You're right, the value isn't just speed—it's about integration. My goal was to build a single tool that replaces the entire grep | jq | awk | tail pipeline.
While Nushell is awesome for general structured data, LogLens is purpose-built for logs with features like built-in percentile stats (stats describe), structured watching (watch --where), and log context (-C 5) that are all designed to work together. The combined use of "query", "watch", and "tui" makes it very fast to pinpoint the exact logs you need.
The free search is the grep replacement, but the Pro tools are where the integrated workflow really shines. Appreciate you checking it out!