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Tessera

Data contract coordination for data warehouses.

Tessera helps data teams coordinate schema changes across producers and consumers. When a producer wants to make a breaking change, consumers are notified and must acknowledge before the change goes live.

Why Tessera?

Data teams face a common problem: breaking changes break pipelines.

  • A data engineer renames a column
  • Downstream dashboards break
  • Analysts discover it days later
  • Everyone scrambles to fix it

Tessera solves this by making breaking changes explicit:

  1. Producers publish contracts - JSON Schema definitions of their data assets
  2. Consumers register dependencies - Teams declare which assets they depend on
  3. Breaking changes require acknowledgment - Before a breaking change goes live, all consumers must acknowledge

Key Features

  • Schema Diffing - Automatically detect breaking vs non-breaking changes
  • Consumer Registration - Track who depends on what
  • Proposal Workflow - Coordinate breaking changes across teams
  • dbt Integration - Sync contracts from your dbt manifest
  • Audit Logging - Track all contract changes and data quality events
  • Web UI - Visual interface for managing contracts and proposals

Quick Example

import httpx

# Publish a contract for your model
response = httpx.post(
    "http://localhost:8000/api/v1/assets/my-asset-id/contracts",
    json={
        "schema": {
            "type": "object",
            "properties": {
                "user_id": {"type": "integer"},
                "email": {"type": "string"},
                "created_at": {"type": "string", "format": "date-time"}
            },
            "required": ["user_id", "email"]
        },
        "compatibility_mode": "backward"
    },
    headers={"Authorization": "Bearer your-api-key"}
)

If you later try to remove email (a breaking change), Tessera will:

  1. Create a Proposal instead of publishing immediately
  2. Notify all registered consumers
  3. Wait for acknowledgments before allowing the change

Getting Started

Architecture

┌─────────────────┐     ┌─────────────────┐
│  dbt Project    │────▶│    Tessera      │
│  (manifest.json)│     │    Server       │
└─────────────────┘     └────────┬────────┘
                                 │
        ┌────────────────────────┼────────────────────────┐
        │                        │                        │
        ▼                        ▼                        ▼
┌───────────────┐      ┌─────────────────┐      ┌───────────────┐
│   Producer    │      │    Consumer     │      │   Consumer    │
│   Team A      │      │    Team B       │      │   Team C      │
└───────────────┘      └─────────────────┘      └───────────────┘

License

Tessera is open source under the MIT License.