Plain-English definitions of the concepts behind Finlynq — the open- source, MCP-first, end-to-end-encrypted personal finance app.
An MCP server is a program that exposes tools and data to AI assistants through the Model Context Protocol (MCP) — an open standard introduced by Anthropic in 2024 that lets any compatible AI client (Claude, Cursor, Windsurf, and others) call those tools in a uniform way. A personal-finance MCP server lets an AI assistant securely query and act on your financial data without custom integrations or copy-pasting exports.
Envelope encryption is a two-layer key scheme: your data is encrypted with a Data Encryption Key (DEK), and the DEK itself is encrypted ("wrapped") by a separate Key Encryption Key (KEK). It is the standard pattern for protecting data so that the key needed to read it is never stored in the clear alongside the data.
Self-hosted personal finance means running a personal finance manager (PFM) on infrastructure you control — your own server, homelab, or VPS — instead of a vendor's cloud. You own the database, the backups, and the network boundary, and your financial data never has to leave hardware you trust.
A zero-knowledge personal finance app is designed so that the operator running the service cannot read your sensitive data, even though it is stored on their servers. The encryption keys are derived from something only you know (your password), so the plaintext is mathematically inaccessible to anyone without it.
Lot-tracked cost basis means recording every purchase of a security as a separate "lot" — with its own quantity, price, and date — so that when you sell, the realized gain is computed against the specific shares sold rather than a single blended average. It produces accurate, tax-relevant gain figures, especially across multiple buys at different prices.