---
title: Source configuration
description: How to setup sources in YAML file
---

# Source configuration




The `dlt.yml` file enables a fully declarative setup of your data source and its parameters. It supports built-in sources such as REST APIs, SQL databases, and cloud storage, as well as any custom source you define.

Credential placeholders for the defined sources are automatically generated in `.dlt/secrets.toml`. Alternatively, configuration may also be provided directly within `dlt.yml`.


## REST API

The built-in `rest_api`-type enables configuration of [REST-based integrations](../../../dlt-ecosystem/verified-sources/rest_api/basic.md). Multiple endpoints can be defined under a single source.


```yaml
sources:
  pokemon_api:
    type: rest_api
    client:
      base_url: https://pokeapi.co/api/v2/
      paginator: auto
    resource_defaults:
      primary_key: name
    resources:
      - pokemon
      - berry
      - 
        name: encounter_conditions
        endpoint:
          path: encounter-conditions
          params:
            offset:
              type: incremental
              cursor_path: name
        write_disposition: append
```

* `type: rest_api`: Specifies the use of the built-in REST API source.
* `client.base_url`: Sets the root URL for all API requests.
* `paginator: auto`: Enables automatic detection and handling of pagination.
* `resource_defaults`: Contains the default values to configure the dlt resources. This configuration is applied to all resources unless overridden by the resource-specific configuration.
* Each item in `resources`defines an endpoint to extract. Simple entries like `pokemon` and `berry` will fetch from `/pokemon` and `/berry`, respectively.
* The `encounter-conditios` resource uses an advanced configuration:
  * `path`: Point to the `/encounter-condition` endpoint.
  * `params.offset`: Enables incremental loading using the `name` field as the cursor.
  * `write_disposition: replace`: Replaces the destination dataset with whatever the source produced on this run.



## SQL database

For SQL-base extractions that require no table-specific parameter configuration, it's possible to initialize `type: sql_database` and declare multiple tables at once.
 
### General SQL database source

```yaml 
sources:
   sql_source:
    type: sql_database
    table_names: 
      - family
      - clan
    incremental:
        cursor_path: updated
        initial_value: 2023-01-12T11:21:28Z 
```

This defines a connection to a SQL database with incremental loading applied across multiple tables.

* `type: sql_database`: Specifies the SQL database connector.

* `table_names`: List of tables to extract.

* `incremental`: Global configuration for incremental extraction.

### Table-specific configuration

For table specific configurationssettings such as different `primary_key`s, individual tables can be defined as standalone sources using the `sql_table` type.


```yaml
sources: 
  sql_family:
      type: sql_database.sql_table
      table: family
      incremental:
        cursor_path: updated
        initial_value: 2023-01-12T11:21:28Z 
      primary_key: rfam_id
```

* `type: sql_table`: Indicates a single-table extraction.

* `table`: Name of the table to extract.

* `incremental`: Enables incremental loading for the table.

* `primary_key`: Specifies the table's unique identifier for deduplication and merges.


## Filesystem

Filesystem sources can be set via the `readers` type and the filesystem specific resources can be called via the CLI `run pipeline` command.


```yaml
sources: 
 file_source:
    type: filesystem.readers
    bucket_url: file://Users/admin/Documents/csv_files
    file_glob: '*.csv'
```

`dlt pipeline file_pipeline run --resources read_csv`



:::tip
Source **type** is used to refer to the location in Python code where the `@dlt.source` decorated function is present. You can
always use a full path to a function name in a Python module, but we also support shorthand and relative notations. For example:
* `rest_api` will be expanded to `dlt.sources.rest_api.rest_api` where `dlt.sources.rest_api` is a Python module in OSS dlt and `rest_api` is a name of a function in that module.
* `github.source` will be expanded to `sources.github.sources` in the current project.
* `filesystem.readers` will be expanded to `dlt.sources.filesystem.readers`

If the **type** cannot be resolved, dltHub will provide you with a detailed list of all candidate types that were looked up
so you can make required corrections.
:::