Chat with contracts: an open-source legal AI stack

What it does

Mike is a full-stack legal document assistant built on a familiar JavaScript stack: a Next.js frontend, an Express backend, Supabase for authentication and Postgres, and R2-compatible object storage. Users upload documents into projects and chat with them via LLMs. It also handles DOC and DOCX conversion to PDF through a local LibreOffice installation, keeping document processing on your own infrastructure.

The interesting bit

The project treats AI providers as interchangeable utilities rather than lock-in: it supports Anthropic, Google Gemini, and OpenAI, letting admins set instance-wide keys or allowing individual users to bring their own in the account settings. That flexibility is unusual for a domain-specific tool like legal tech, where most competitors tether you to a single proprietary model.

Key highlights

• Multi-model support with per-user or instance-wide API key management
• Full Supabase schema and incremental migrations for self-hosted deployments
• R2, MinIO, or S3-compatible object storage for document files
• DOC/DOCX to PDF conversion via local LibreOffice installation
• 3,861 GitHub stars and actively maintained at mikeoss.com

Caveats

• Requires LibreOffice installed locally for Microsoft Word document conversion
• Supabase Auth’s built-in email confirmation is heavily rate-limited and may fail on newer projects
• Needs separate accounts and keys for Supabase, object storage, and at least one LLM provider

Verdict

Worth a look if you need a private, self-hosted alternative to cloud legal AI tools and don’t mind assembling the infrastructure. Skip it if you want a managed SaaS with zero backend maintenance.