OpenSEO: The Open-Source Semrush That Costs What You Actually Use

Semrush is $140/month. Ahrefs is $129/month. Both are built for agencies managing dozens of clients. For a developer running a handful of sites, you pay for features you will never touch. OpenSEO is the exit: pay-as-you-go SEO tooling via your own DataForSEO API key, modern focused UI, MCP server for AI agents. 20,000 GitHub stars, MIT licensed, TypeScript, Cloudflare Workers.

What OpenSEO is

OpenSEO (openseo.so, github.com/every-app/open-seo) is an open-source SEO platform. MIT licensed, TypeScript, Cloudflare Workers + D1 + KV. Built by the every-app team. Hosted at $10/month. Self-hosted free using your own DataForSEO API key. Core model: OpenSEO is the UI and workflow layer; SEO data comes from DataForSEO's API, which you pay for directly at cost. Self-hosted costs 28% less than hosted.

Core SEO workflows

Keyword research - search volume, KD, CPC, SERP features, related keywords via DataForSEO database. Rank tracking - position for target keywords over time, daily updates, SERP features. Competitor insights - keywords competitors rank for, top pages, organic traffic, keyword gaps. Backlinks - backlink profile, referring domains, anchor text, new and lost links. Site audits - technical SEO issues: broken links, missing meta tags, duplicate content, page speed, Core Web Vitals. AI Visibility - track how your content appears in AI-generated responses as search shifts from blue links to LLM answers.

MCP server and Agent Skills

OpenSEO exposes an MCP server. Claude Code, OpenClaw, Hermes, and any MCP-compatible agent can use your SEO data directly as tool calls - keyword research, rank checks, backlink data - without switching context. Agent Skills are pre-built reusable workflows that guide agents through SEO tasks. Community-contributed and customizable. Research keywords for a blog post from inside the same session where you write the content.

Pay-as-you-go pricing

No subscription. Pay DataForSEO directly for API calls you make. Rough estimates: keyword data from $0.0005/keyword, backlink data from $0.01/domain, site audit from $0.0005/page crawled. A typical blog post research session costs $0.05-0.20.

Self-hosting

Cloudflare (recommended) - Cloudflare Workers + D1 + KV, works on free plan, internet-facing multi-device or team use. Docker - local/personal testing. Both require a DataForSEO API key from dataforseo.com.

vs Semrush and Ahrefs

Semrush and Ahrefs win on: depth of proprietary crawl databases, agency reporting, UI polish, dedicated support. OpenSEO wins on: no subscription, pay per use, open source and forkable, MCP server for AI agents, modern focused UI without enterprise bloat. The right question: does it cover the workflows you actually use, for the cost you are willing to pay?

Who it is for

Good fit: developers and indie makers who need core SEO workflows without a $140/month subscription; teams using AI agents who want SEO data via MCP; technical users who want to fork and customize; anyone integrating SEO into automated workflows.

Not ideal: agencies needing Semrush white-label reporting; teams needing Ahrefs depth of historical backlink data; non-technical users who don't want to manage a DataForSEO key or Cloudflare deployment.

My take

OpenSEO solves the right problem: SEO tooling is overpriced for what most developers actually need. Pay-as-you-go via DataForSEO is genuinely better economics for light-to-medium usage than any monthly subscription. The MCP server is the differentiated feature - SEO data accessible to AI agents in the same workflow where you're writing content is a meaningfully different way of working. 20k GitHub stars in a niche tool category suggests the market agrees.