The Minimalist Data Contract

From five fields to a full-fledged contract in under 30 minutes: because data, like brownies, doesn’t need 20 ingredients to taste good.

A good friend of mine asked me what the minimal data contract you can build is. Instead of debating via email, I told him, Philippe, give me a few days. And here it is: let's explore the minimalist data contract together.

If you can make brownies in one bowl with five ingredients, you can make a data contract in one table with five fields. That’s the whole idea of the Minimalist Data Contract: less fuss, fewer moving parts, and just enough structure to bake trust into your data.

Like Minimalist Baker‘s motto: 10 ingredients or less, one bowl, or 30 minutes or less. Challenge accepted, I’ll do the same for data contracts:

• ≤10 fields

• 1 table

• 30 minutes or less

Let's apply the Minimalist Baker's approach to data contracts.

Step 1: The One-Table ERD (Your Mixing Bowl)

Our data is about customers. One entity, one bowl.

A simple customer entity.

Only five fields can define a customer: an identifier, a first and last name, an email, and a phone number.

Step 2: The DDL (The Batter)

Just enough SQL to give structure.

-- Table: Customer
CREATE TABLE Customer (
    customer_id SERIAL PRIMARY KEY,
    first_name VARCHAR(255),
    last_name VARCHAR(255) NOT NULL,
    email VARCHAR(255) UNIQUE NOT NULL,
    phone VARCHAR(20)
);

That’s it. No joins, no indexes beyond the primary key. A single, wholesome layer. In all fairness, this step is not even required at this stage, or skip Step 1. It's about giving context.

Step 3: The Data Contract (The Recipe Card)

Now we wrap it in an Open Data Contract Standard (ODCS) YAML. Think of it as the recipe card taped to the fridge—everyone can see what goes in and how it’s meant to be used.

apiVersion: "v3.1.0"
kind: "DataContract"
id: "9f0429b0-4bd7-4ebd-aac9-3b68cf9faafc"
version: "v0.1.0"
status: "proposed"

schema:
- name: "Customer"
  properties:
  - name: "customer_id"
  - name: "first_name"
  - name: "last_name"
  - name: "email"
  - name: "phone"

That’s a complete, valid contract in its most minimal form. It links directly to your schema, so producers and consumers are literally on the same page.

Step 4: Enhancing the Data Contract (The Icing on The Cake)

You are now entering the positive cycle of enhancing your data contract. In this next iteration, I mostly:

• Add documentation.

• Add details about the fields.

apiVersion: "v3.0.2"
contractCreatedTs: "2025-05-09T21:34:58.759+00:00"
dataProduct: ""
description:
  purpose: "DDL upload for contract generation"
  usage: "Analytics"
  limitations: "None defined"
domain: "Customer"
id: "34cae6d7-7648-38b2-8f66-8db79e1e2ce4"
kind: "DataContract"
name: "CustomerContract"
status: "draft"
tenant: "QuantumClimate"
version: "v0.2.0"

schema:
- logicalType: "object"
  name: "Customer"
  physicalName: "Customer"
  physicalType: "table"
  description: "Contains basic customer information"
  properties:
  - logicalType: "number"
    name: "customer_id"
    physicalName: "customer_id"
    physicalType: "SERIAL"
    primaryKey: true
    required: true
  - logicalType: "string"
    name: "first_name"
    physicalName: "first_name"
    physicalType: "VARCHAR (255)"
  - logicalType: "string"
    name: "last_name"
    physicalName: "last_name"
    physicalType: "VARCHAR (255)"
    required: true
  - logicalType: "string"
    name: "email"
    physicalName: "email"
    physicalType: "VARCHAR (255)"
    required: true
  - logicalType: "string"
    name: "phone"
    physicalName: "phone"
    physicalType: "VARCHAR (20)"
    description: "Phone number, assuming country code is baked in"

It adds some context that will help your consumers. You can continue adding iteratively: data quality rules, SLA, team information, and more. Your contract's maturity will increase.

Step 5: Packaging in a Data Product (Putting The Cake in a Box)

As a bonus step, here is how your data contract becomes the definition of an output port for your data product.

apiVersion: v1.0.0
kind: DataProduct

name: Customer Data Product
id: 2abf58db-8672-43a2-88fa-787e6c37be46
status: proposed

description:
  purpose: Enterprise view of a customer.

outputPorts:
- name: customerTable
  description: "Customer Table"
  contractId: 34cae6d7-7648-38b2-8f66-8db79e1e2ce4

Simple enough, no? So why not package your contracts systematically?

Resources & Next Steps

A few additional resources:

• All those examples are on GitHub. Go there, and star it!

• Interactive tutorials to help you automate some of those operations. The first tutorial will really help with the scenario you just read.

• Bitol's open standards: ODCS and ODPS.

Why Minimalist Works

A minimalist contract is not about cutting corners. It’s about:

• Clarity: one table, five fields.

• Speed: start in 30 minutes, ship value today.

• Iterability: add SLAs, ownership, lineage, and governance later, the frosting on your cupcake.

Remember: you don’t need a wedding cake for your first data product. Bake the cupcake, share it, and improve the recipe over time (and if you need a beta tester, I am eager to test your recipes).

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Closing Bite

The Minimalist Baker proves you can make great food with fewer ingredients. The Minimalist Data Contract proves you can build great data products with fewer fields.

Five fields. One table. One contract. One product.

Ready in under 30 minutes.

Photo credit: Ron Lach.