> ## Documentation Index
> Fetch the complete documentation index at: https://tyk-update-tt-17927-release-main-docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Tyk Gateway Configuration Options

> Configuration options and environment variables for Tyk Gateway.

You can use environment variables to override the config file for the Tyk Gateway. The Gateway configuration file can be found in the `tyk-gateway` folder and by default is called `tyk.conf`, though it can be renamed and specified using the `--conf` flag. Environment variables are created from the dot notation versions of the JSON objects contained with the config files.
To understand how the environment variables notation works, see [Environment Variables](/tyk-oss-gateway/configuration).

All the Gateway environment variables have the prefix `TYK_GW_`. The environment variables will take precedence over the values in the configuration file.

### Environment Variable Type Mapping

When configuring Tyk components using environment variables, it's important to understand how different data types are represented. The type of each variable is based on its definition in the Go source code. This section provides a guide on how to format values for common data types.

| Go Type                  | Environment Variable Format                | Example                                                              |
| ------------------------ | ------------------------------------------ | -------------------------------------------------------------------- |
| `string`                 | A regular string of text.                  | `TYK_GW_SECRET="mysecret"`                                           |
| `int`, `int64`           | A whole number.                            | `TYK_GW_LISTENPORT=8080`                                             |
| `bool`                   | `true` or `false`.                         | `TYK_GW_USEDBAPPCONFIG=true`                                         |
| `[]string`               | A comma-separated list of strings.         | `TYK_PMP_PUMPS_STDOUT_FILTERS_SKIPPEDAPIIDS="api1,api2,api3"`        |
| `map[string]string`      | A comma-separated list of key:value pairs. | `TYK_GW_GLOBALHEADERS="X-Tyk-Test:true,X-Tyk-Version:1.0"`           |
| `map[string]interface{}` | A JSON string representing the object.     | `TYK_GW_POLICIES_POLICYSOURCE_CONFIG='{"connection_string": "..."}'` |

<Note>
  For complex types like `map[string]interface{}`, the value should be a valid JSON string. For `[]string` and `map[string]string`, ensure there are no spaces around the commas unless they are part of the value itself.
</Note>

### tyk lint

In **v2.4** we have added a new `tyk lint` command which will validate your `tyk.conf` file and validate it for syntax correctness, misspelled attribute names or format of values. The Syntax can be:

`tyk lint` or `tyk --conf=path lint`

If `--conf` is not used, the first of the following paths to exist is used:

`./tyk.conf`
`/etc/tyk/tyk.conf`

<GatewayConfig />