Mermaid is the de-facto declarative diagram language for engineering documentation — a few lines of text describe a flowchart, sequence diagram, state machine or ERD, and a renderer produces the SVG. Until now, customers wanting Mermaid output had two paths : a client-side JavaScript renderer (heavy, slow, JS-only) or an external rendering service (operational dependency, latency, security review). The platform's eighteen-service mesh now ships its own Mermaid microservice and removes both.
- HTTP and gRPC. Both wire protocols are exposed ; in-cluster callers use gRPC, external callers HTTP. Same request envelope, same response shape.
- Full Mermaid coverage. Flowcharts, sequence diagrams, state machines, class diagrams, ERDs, Gantt charts, pie charts, journey diagrams, git-graph — all of Mermaid 10's diagram types render server-side.
- Production-grade SVG. Output validates against the SVG 1.1 spec, is print-safe and embeds cleanly in PDF documents rendered through the document-processing microservice.
- Platform-managed caching. Identical diagram requests return cached SVG, with the cache key keyed on a normalised hash of the DSL ; busy documentation surfaces serve repeat renders from cache.
The pattern matters beyond the diagram itself : every external rendering dependency that a regulated customer would have to security-review separately is one the platform can absorb as a microservice on the same operational surface. UML collaboration diagrams, ERDs and sequence diagrams now live in the customer's perimeter, not in a third-party SaaS.