Open Source Reporting Tools
A report that has to be a pixel-perfect PDF or a fillable DOCX is a different problem from a chart on a screen - it has to render the same way for an auditor, a customer, and a printer, generated on demand from live data and a fixed template. The open source engines here turn your data and layouts into documents inside your own systems, so the generation runs wherever your application does and the output never depends on an outside service to produce a file you're legally on the hook for.
Metabase
Open source analytics for asking questions, building dashboards, and embedding BI
Lightdash
Open-source BI platform for dbt teams that defines metrics in dbt and shares charts and dashboards
Carbone
Open source report generator that turns JSON data and office templates into PDF, DOCX, XLSX, ODT, and more
JasperReports
Free Java reporting library for pixel-perfect documents in HTML, PDF, Excel, Word, and more
jsreport
Open-source reporting platform for designing and rendering reports with JavaScript templating
SEOnaut
Open source SEO auditing and reporting tool for site scans, issue severity, and technical SEO checks
Eclipse BIRT
Open source reporting and data visualization for Java applications, built around the Eclipse platform
Pentaho Reporting
Java reporting library and desktop designer for generating output to PDF, Excel, XML, CSV, and printers
Site Audit SEO
Web service and CLI for SEO site audits with crawl, Lighthouse checks, and browser reports