Implement Palantir Foundry reference architecture with best-practice project layout. Use when designing new Foundry integrations, planning data pipeline architecture, or establishing patterns for Ontology-driven applications. Trigger with phrases like "palantir architecture", "foundry best practices", "foundry project structure", "how to organize palantir".
Production-ready architecture for Foundry-integrated applications. Covers the standard data pipeline pattern (ingest > clean > model > serve), Ontology design, external API integration, and multi-repo project layout.
palantir-core-workflow-a (transforms) and palantir-core-workflow-b (Ontology)┌─────────────┐ ┌──────────────┐ ┌─────────────┐ ┌───────────┐
│ Raw Layer │────>│ Clean Layer │────>│ Model Layer │────>│ Ontology │
│ (ingested) │ │ (validated) │ │ (enriched) │ │ (objects) │
└─────────────┘ └──────────────┘ └─────────────┘ └───────────┘
↑ Connectors @transform_df @transform_df Object types
↑ REST sync null checks joins, aggs Link types
↑ File upload type casting ML features Actions
Foundry Project: "Customer Analytics"
├── Datasets/
│ ├── raw/ # Ingested from sources
│ │ ├── raw_orders # REST connector → CRM
│ │ ├── raw_customers # JDBC connector → DB
│ │ └── raw_products # File upload (CSV/Parquet)
│ ├── clean/ # Validated, typed
│ │ ├── clean_orders # Nulls removed, dates parsed
│ │ ├── clean_customers # Deduped, normalized
│ │ └── clean_products # Schema enforced
│ └── model/ # Enriched, analytics-ready
│ ├── order_enriched # Joined with customer + product
│ ├── customer_360 # Aggregated customer view
│ └── daily_summary # Time-series aggregation
├── Code Repositories/
│ ├── pipeline-ingestion/ # Connectors and raw → clean
│ ├── pipeline-analytics/ # Clean → model transforms
│ └── ontology-actions/ # Action implementations
└── Ontology/
├── Object Types: Customer, Order, Product
├── Link Types: Customer→Orders, Order→Products
└── Actions: createOrder, updateCustomerSegment
# External app consuming Foundry Ontology via Platform SDK
my-external-app/
├── src/
│ ├── foundry/
│ │ ├── client.py # Singleton FoundryClient
│ │ ├── objects.py # Object query helpers
│ │ ├── actions.py # Action wrappers
│ │ └── cache.py # TTL cache layer
│ ├── api/
│ │ ├── routes.py # REST endpoints
│ │ └── webhooks.py # Foundry event handlers
│ └── main.py
├── tests/
│ ├── conftest.py # Mocked FoundryClient
│ ├── test_objects.py
│ └── test_actions.py
├── .env # FOUNDRY_HOSTNAME, credentials
└── requirements.txt
| Pattern | When to Use | Example |
|---|---|---|
| Hub-and-spoke | Central entity with many relationships | Customer → Orders, Tickets, Payments |
| Event sourcing | Audit trail needed | OrderEvent (created, shipped, delivered) |
| Computed properties | Derived values | totalRevenue on Customer (sum of orders) |
| Composite actions | Multi-step mutations | processReturn: update order + create credit + notify |
┌──────────────────────────────────────────┐
│ Layer 1: Network (VPN/private link) │
├──────────────────────────────────────────┤
│ Layer 2: OAuth2 (service user per app) │
├──────────────────────────────────────────┤
│ Layer 3: Scopes (minimum per app) │
├──────────────────────────────────────────┤
│ Layer 4: Project roles (Viewer/Editor) │
├──────────────────────────────────────────┤
│ Layer 5: Marking (data classification) │
└──────────────────────────────────────────┘
| Architecture Issue | Symptom | Fix |
|---|---|---|
| Circular dependencies | Builds fail | Restructure pipeline DAG |
| Missing clean layer | Bad data in model | Always validate between raw and model |
| Monolithic transforms | Slow builds | Split into focused transforms |
| No caching | API rate limits | Add TTL cache layer |
For data handling and compliance, see palantir-data-handling.