Principles

OpenTRMS is built around a small set of non-negotiables. They explain why the event store is append-only, why the same domain services back both the REST API and the MCP server, and why nothing about pricing or risk is hidden.

Open by construction. The logic that prices your book is the code in the repository — no license metering, no black box.
Self-hosted. The platform runs in your VPC, against your PostgreSQL. Your positions never leave your infrastructure.
Audit-first. Every state change appends a typed, hashed event. UPDATE and DELETE are revoked at the database level.
One core, many surfaces. REST, MCP and embedded Java all call the same domain services with the same scopes and approval chains.

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Reference content is being expanded. The Quickstart is the fastest way to see these principles in action.