SOA System Landscape — MIT Open Learning
Generated 2026-06-24 17:02 UTC · c4gen dev
The holistic, whole-system view: every mapped MIT Open Learning system and the cross-service data flows between them, composed from the 10 per-system C4 models. Use it for onboarding and SOA-wide decisions — surfacing dependencies, cycles, and the shared platform every system leans on. Each per-system guide drills into containers and flows; this page is the map of maps.
How to read these diagrams
These are C4 model diagrams (C4-PlantUML). Read them top-down: System Context (the whole SOA) → Container (one system's runtime units) → Dynamic (a single data flow, step by step).
- People are rounded boxes; systems and containers are rectangles; databases and queues have distinct shapes.
- Each arrow is a data flow labelled with what moves.
- Solid arrows are synchronous (request/response, caller blocks).
- Amber dashed arrows are asynchronous (queued, scheduled, or event-driven — caller does not block).
- Drag to pan, scroll to zoom. Boxes with a link drill into the next level.
System dependency matrix
System-to-system coupling aggregated from the curated cross-service flows across all models (container-level flows lifted to their owning system; deduped).
| System | Depends on → |
|---|---|
| MITx Online | Keycloak (SSO), MITx Online Open edX |
| MITx Online Open edX | Keycloak (SSO), MITx Online |
| MITx Pro | xPRO Open edX |
| xPRO Open edX | — |
| MicroMasters | MIT Learn, MITx Online, MITx Online Open edX |
| OCW Studio | MIT Learn |
| ODL Video Service | Keycloak (SSO), MITx Online Open edX, xPRO Open edX |
| MIT Learn | APISIX Gateway, LiteLLM Proxy, MITx Online, MITx Pro, MicroMasters, ODL Video Service |
| learn-ai | Keycloak (SSO), LLM Provider, LiteLLM Proxy, MIT Learn |
| OL Data Platform | MIT Learn, MITx Online, MITx Pro, MicroMasters, OCW Studio, ODL Video Service |
Cross-service cycles
Computed over the owned internal systems only (Open edX included) — the shared gateway/identity infra (APISIX, Keycloak) sits in nearly every path and would manufacture cycles that aren't harmful coupling.
SOA-wide dependency cycles
micromasters → mit-learn → micromastersmitxonline → mitxonline-openedx → mitxonline
Shared platform & libraries
The apps share a common platform: APISIX (gateway, OIDC), Keycloak (SSO), and HashiCorp Vault (secrets/credentials). Open edX sits behind the course-delivery apps as a first-class internal system (drill in for its map). Shared Django/identity libraries — ol-django and ol-keycloak — are used across systems (not drawn as nodes).
Composition clean
Every cross-service flow endpoint resolved to a known system or shared platform node.
Keeping this current
This page is composed from architecture_maps/models/*.yaml by
architecture_maps/c4gen. Update a per-system model and regenerate with
c4gen landscape; CI fails if the committed page/diagram drift.