We often see people talk about data products or data as a product, and they usually tackle the topics of:

• Concepts and how to think about data products.
• Users and producers: Roles, responsibilities and blame around data products.
• Data: Data quality and governance that is part of those products, data as a product.
• Code: The code or technology powering the pipelines.
• Infra: the infrastructure data products are run on.

What we do not see is any practical advices or examples of how to implement these products. While the concepts often define data products as something with a use case, they fail to discuss the importance a user manual, or documentation.

The role of the user manual

So what is a data product?

A data product is a self-contained piece of data-powered software that serves a single use case. For example, it could be a pipeline that loads Salesforce data to Snowflake, or it could be an ML model hosted behind an api. Many talk about data products as some kind of inter-company exchange - like one company does it and another reuses it. However, the prevalent case is when we have a team building it and another using it - just like a "production backend", these internal data tools help the business run their processes and are an integral part of the company and their product.

Always consider the use case for the description of the product, but the entire technical stack as part of the product - so, the code and data responsible for enabling the use case are part of the product.

Examples of data products:

• Lead ranking algorithm that helps the sales team prioritise their leads based on rules and maybe data.
• ROI calculator that enables the marketing team to optimise profits or expansion via better bidding and reinvestment efforts.
• Data pipeline that creates a report that is core for the finance team, containing things the finance team defines and wants.
• A data contract that alerts if salesforce leads do not have a corresponding company in the production system.
• A series of calculations that segment customers by various features we can use for targetting.
• A data mart that enables the CRM team select subsets of users by ad-hoc defined behavior.
• A data pipeline that provides externals with data.
• A report which we offer via api for external consumption.
• An api endpoint that produces a content recommendation for a particular website slot.
• A dashboard that enables the Account Management team to prioritise who they should reach out to, to enable them to reach their goals.

What makes a data pipeline a data product?

The term product assumes more than just some code. A "quick and dirty" pipeline is what you would call a "proof of concept" in the product world and far from a product.

Who the duck wrote this trash??? Ahhhhh it was me :( ...

To create a product, you need to consider how it will be used, by whom, and enable that usage by others.

A product is something that you can pick up and use and is thus different from someone’s python spaghetti.

For example, a product is:

• Reusable: The first thing needed here is a solid documentation that will enable other users to understand how to use the product.
• Robust: Nothing kills the trust in data faster than bad numbers. To be maintainable, code must be simple, explicit, tested, and documented :)
• Secure: Everything from credentials to data should be secure. Depending on their requirements, that could mean keeping data on your side (no 3rd party tools), controlling data access, using SOC2 compliant credential stores, etc.
• Observable: Is it working? how do you know? you can automate a large part of this question by monitoring the volume of data and schema changes, or whatever other important run parameters or changes you might have.
• Operationizable: Can we use it? do we need a rocket scientist, or can little Bobby Tables use it? That will largely depend on docs and the product itself.

So what is a data product made of?

Let’s look at the high-level components:

1. Structured data: A data product needs data. The code and data are tightly connected - an ML model or data pipeline cannot be trained or operate without data. Why structured? because our code will expect a structured input, so the data is going to be either explicitly structured upfront (”schema on write”), or structured implicitly on read (”schema on read”).
2. Code.
3. Docs for usage - Without a user manual, a complex piece of code is next to unusable.

And which docs are needed?

We will need top level docs, plus some for each of the parts described above.

1. Top level: Purpose of existence for the data product. The code describes the what and how - So focus the readme on the “why” and top level “what”. Similar to a problem description, this document explains what problem your product solves and enables the reader to understand the cost and impact it might have to use your product.
2. Structured data:
   1. A data dictionary enables users to gain literacy on the dataset.
   2. Maintenance info: information about the source, schema, tests, responsible person, how to monitor, etc.
3. Code & Usage manual: This one is harder. You need to convey a lot of information effectively, and depending on who your user is, you need to convey that information in a different format. According to the best practices on the topic of docs, these are the 4 relevant formats you should consider. They will enable you to write high-quality, comprehensive and understandable docs that cover the user’s intention.
   • learning-oriented tutorials;
   • goal-oriented how-to guides;
   • understanding-oriented discussions;
   • information-oriented reference material.

Some examples from dlt

Dlt is a library that enables us to build data pipelines. By building with dlt, you benefit from simple declarative code and accessible docs for anyone maintaining later. Assuming you use dlt or your own loading approach in your data platform, you will want to document both the tool used, to enable people to modify things, and the popelines themselves to describe semantically what is being loaded. Here are some examples of how you could do that:

• Top level: Here is our attempt for dlt itself - the intro doc. You could describe the problem or use case that the pipeline solves.
• Data dictionary: Schema info belongs to each pipeline and can be found here. To get sample values, you could write a query. We plan to enable its generation in the future via a “describe” command.
• Maintenance info: See how to set up schema evolution alerts. You can also capture load info such as row counts to monitor loaded volume for abnormalities.
• Code and usage: We are structuring all our docs to follow the best practices around the 4 types of docs, generating a comprehensive, recognisable documentation. We also have a GPT assistant on docs, and we answer questions in Slack for conversational help.

In conclusion

Stop thinking about data, code and docs in isolation - they do not function independently, they are different parts of the same product. To produce quality documentation, focus on the why, let the code show the what and how. and use standard formats for teaching complex tooling.

Want to create data products with dlt? What are you waiting for?

• Dive into our Getting Started.
• Join the ⭐Slack Community⭐ for discussion and help!