---
title: "config.json"
slug: "build-config-json"
updated: 2022-12-13T18:08:19Z
published: 2022-12-13T18:08:19Z
---

> ## Documentation Index
> Fetch the complete documentation index at: https://code.tag.bio/llms.txt
> Use this file to discover all available pages before exploring further.

# config.json

With Tag.bio, you don't always need to go through the arduous process of munging and restructuring your data. By way of a series of structured JSON files, you can tap into a series of powerful data parsing tools to analyze just the data you need.

The basic project structure consists of a *config.json* reference file and a *config* folder at the root of your project. Within the *config* folder are definition files for the *entity_table.json*, *other_tables.json*, and a folder for *parsers*.

## config.json

The *config.json* file contains a series of path references for your *entity_table*, *other_tables*, and *parsers*. The paths are relative to the root of your project.

```
{
  "entity_table": "config/entity_table.json",
  "other_tables": "config/other_tables.json",
  "parsers": "all"
}
```

The *parsers* array can contain the individual parser objects of your project, or the file path for parser files you create. For new projects, you can set the parsers attribute with the string "all", which will automatically infer data types. This can be a handy way to begin your project.

## entity_table.json

The *entity_table* is the master data table for your project. As is common with all table definitions, an *alias* is given by the developer. This *alias* is how the table will be referenced in the future. The *unique_keys* array contains the identifier for the primary entity of the data.

```
{
  "table": "patients.csv",
  "alias": "patients",
  "unique_keys": [
    "ID"
  ]
}
```

## other_tables.json

The *other_tables* reference is how to assign joins from ancillary tables to the *entity_table*. The standard definition for *other_tables* is an array of objects, with each object being a table to join. The *id_columns* attribute is a key:value paired object used to define the linkage from the table being joined and the *entity_table*.

```
[
  {
    "table": "encounters.csv",
    "alias": "encounters",
    "id_columns": {
      "PATIENT": "ID"
    }
  }
]
```

## parsers

The *parsers* array can contain the individual parser objects of your project, or the file path for parser files you create. Parsers are generally bundled together by table or by purpose so that they can be easily located. Check out the [Parser Types](https://tagbio-developer-docs.document360.io/docs/parser-types) page for more info on the variety of parser types available for columns, rows, and matrix parsers.