Question: I tried to export a settings.json as documented in the meteor.js documentation in order to connect my Meteor.js app with an external MongoHQ database :

```
{
    "env": {
        "MONGO_URL" : "mongodb://xxx:xxxx@troup.mongohq.com:10037/xxx"
    }
}

```

with the command : 

```
mrt deploy myapp.meteor.com --settings settings.json

```

It doesn't even work, My app continue to connect the local database provided with the Meteor.app !
My MONGO\_URL env variable didnt changed.

Is there any solution to export my MONGO\_URL env variable to connect an external MongoDB database ? 

I saw that is possible to change it while using heroku or modulus, what about the standard deploying meteor.com solution ?

Answer: 
Create a `lib` folder under the `server` folder and write:

```
Meteor.settings = { //your settings };

```

According to documentation everything inside a folder named `lib` will be executed before anything, so this way we ensure that no code will be execute before this, preventing errors from accessing Metrics that don't exist.

If you're already using the `lib` folder you've to named right to run before anything else that might conflict, check the docs about it.

Enjoy.
The application-configuration package (built in meteor package) contains the code to set mongo\_url. See my answer here <https://stackoverflow.com/a/23485319/2391620>