Axiom vs Highlight.io for Solo Developers

Quick Comparison

Axiom Overview

Axiom is a log and event analytics platform designed around cheap storage and powerful querying. The idea is simple: send all your data to Axiom, and query it when you need to investigate something. No sampling, no tight retention limits, no per-host pricing games.

The free tier is the headline feature for solo developers. 500 GB of ingest per month with 30 days of retention. For reference, that's enough to store millions of log entries from a busy production app. You send structured JSON events to datasets and query them using APL, a language similar to Kusto/KQL from the Azure ecosystem.

I use Axiom as my log dump. Application logs, webhook events, cron job outputs. Everything goes to Axiom. When something breaks, I open the query interface and search for what I need. The speed is impressive even on large datasets, and the cost is hard to argue with.

Highlight.io Overview

Highlight.io combines session replay, error tracking, and log management into one open-source platform. The focus is on understanding the user experience when things go wrong. When an error happens, you don't just see a stack trace. You watch a replay of the user's session, see what they clicked, what network requests fired, and what console errors appeared.

The session replay is what sets Highlight.io apart from most monitoring tools. It records DOM changes so you see a video-like playback of the user's experience. This is incredibly useful for debugging issues that are hard to reproduce from error logs alone.

Highlight.io is fully open-source. You can self-host it or use the cloud version. The free tier includes 500 sessions per month and 1,000 errors. For a small project, that's a reasonable starting point.

Key Differences

Core purpose. Axiom is a data store for logs and events. You query it when you need answers. Highlight.io is a debugging tool for user-facing issues. You watch session replays when users hit problems. They start from different assumptions about what "monitoring" means.

Session replay. Highlight.io offers full session replay. Axiom doesn't. If you need to see what a user did in their browser, Highlight.io is the only option between these two. For UI bugs, form issues, and user confusion, session replay is worth its weight in gold.

Log management scale. Axiom's free tier gives you 500 GB of ingest per month. Highlight.io includes log management but with significantly less volume on the free tier. If you generate large amounts of log data, Axiom handles the volume better.

Error tracking. Highlight.io provides structured error tracking with stack traces tied to session replays. Axiom stores error events as log entries. You can search for errors in Axiom, but there's no automatic grouping, deduplication, or session context. Highlight.io's error tracking is more like Sentry with session replay bolted on. Axiom treats errors as just another type of event.

Query flexibility. Axiom's APL query language is more powerful for complex log analysis. You can aggregate, filter, join, and transform data in ways that Highlight.io's log search can't match. If you need to answer questions like "how many errors of type X occurred per hour over the last 14 days, grouped by API endpoint," Axiom handles that efficiently.

Open source. Highlight.io is fully open-source and self-hostable. Axiom is closed-source SaaS. If self-hosting and code transparency matter, Highlight.io wins on principle.

Frontend vs backend focus. Highlight.io is strongest for frontend and full-stack applications where the user experience is the primary concern. Axiom is backend and infrastructure-focused, where log volume and querying power matter more than user session context.

When to Choose Axiom

• You need large-scale log storage at a low cost
• Complex log querying and analytics are your primary use case
• Your debugging workflow starts with logs, not user sessions
• You want a managed service with generous free tier ingest limits
• Backend systems generate most of your monitoring data

When to Choose Highlight.io

• Frontend debugging with session replay is your top priority
• You want error tracking tied to visual context of user behavior
• Open-source and self-hostable software is important to you
• Your app is user-facing and most bugs surface in the UI
• You want a combined session replay plus error tracking plus logs tool

The Verdict

These tools serve different debugging workflows. Axiom is for when you think "something went wrong in my system, let me search the logs." Highlight.io is for when you think "a user reported a bug, let me watch what they did."

For a solo developer building a user-facing application (SaaS, web app, dashboard), I'd start with Highlight.io. The session replay gives you debugging context that no amount of log searching can replicate. Watching a user struggle with your checkout flow teaches you more in 30 seconds than reading through pages of server logs.

For a solo developer building backend-heavy systems (APIs, data pipelines, cron jobs), I'd start with Axiom. You don't have browser sessions to replay, so the log analytics are more valuable. The 500 GB free tier means you can log everything generously.

If your project has both a frontend and backend (most do), consider running both. Highlight.io for the user-facing layer, Axiom for the backend. Highlight.io's free tier covers your session replay needs, and Axiom's free tier handles your log storage. Together, they give you visibility into both sides of your application at zero cost.