The best open source alternative to Ahrefs is OpenSEO. If that doesn't suit you, we've compiled a ranked list of other open source Ahrefs alternatives to help you find a suitable replacement.
Ahrefs alternatives are mainly SEO Tools. Browse these if you want a narrower list of alternatives or looking for a specific functionality of Ahrefs.
Manage keyword research, backlink analysis, competitor monitoring, and rank tracking without expensive SaaS subscriptions. Self-hostable, MIT-licensed, uses DataForSEO.

OpenSEO is a self-hosted SEO platform built for teams that want full control over their SEO data without paying recurring fees to tools like Semrush or Ahrefs. It's MIT-licensed and runs on Docker or Cloudflare, so you own the infrastructure and the data.
The platform covers the core workflows most SEO teams rely on:
It connects to the DataForSEO API, which means you bring your own API key and pay for data directly rather than through a platform markup. That model works well for agencies or in-house teams with predictable data needs who want to cut out the subscription layer.
Because the source is fully open, teams can fork the codebase and build custom workflows on top of it. That's a real advantage if your SEO process doesn't fit neatly into what commercial tools offer. An Ubersuggest or Semrush subscription locks you into their interface; OpenSEO doesn't.
A hosted option exists for teams that don't want to manage their own infrastructure, but self-hosting is the primary path and keeps costs predictable.