Performance
Performance tools are for finding and fixing slow pages — the kind of work every indie hacker eventually hits and would rather not build from scratch. 7 tools are listed here, each picked and written up individually rather than pulled from an affiliate feed. AppSignal is usually the first one people try: APM sized for a small team's budget and Ruby/Elixir/Node stack, without New Relic's enterprise sprawl. Blackfire takes a different angle — if you're debugging a slow PHP or Python app, this shows you the actual function-level cost, not just 'it's slow.' And Grafana k6 is worth a look too: script realistic load tests in JS/TS and find out where your API actually falls over, before your users do. Every listing below includes the actual tradeoff, not marketing copy, so you can pick based on what you're building instead of what ranks highest in a sponsored roundup elsewhere.
APM sized for a small team's budget and Ruby/Elixir/Node stack, without New Relic's enterprise sprawl.
If you're debugging a slow PHP or Python app, this shows you the actual function-level cost, not just 'it's slow.'
Script realistic load tests in JS/TS and find out where your API actually falls over, before your users do.
The fastest way to get a page-speed report a non-engineer can actually read, though the good stuff now sits behind a paywall.
The default answer to 'why is production slow' once a team is big enough to afford full-stack tracing across every service.
For teams who need to watch Core Web Vitals drift over time instead of running one-off checks — built on WebPageTest's guts.
Free and open, and still the deepest way to see exactly why a page is slow — waterfalls and filmstrips, not vague scores.