---
sidebar_position: 6
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:::tip
This is version 3 api only!!
:::

# Services

:::tip
TLDR: The direct upgrade to useContainer. if you set up a bot with create-bot, check dependencies.d.ts. 
Dependencies are the types that Services uses.
:::

You need someway to use dependencies in your command module. Services to the rescue!
```ts title="src/dependencies.d.ts"
import { CoreDependencies, Singleton } from '@sern/handler'
import { Client } from 'discord.js'

interface Dependencies extends CoreDependencies { 
    '@sern/client': Singleton<Client>
}

```
Recall, some keys in Dependencies are special. 

> Special key dependency must implement its contracts.
>  - `@sern/client`: Your discord client. -> [Emitter](../../api/interfaces/Emitter)
>  - `@sern/logger`: Log data -> [Logging](../../api/interfaces/Logging) 
>  - `@sern/errors`: Handling errors and lifetime -> [ErrorHandling](../../api/interfaces/ErrorHandling)
>  - `@sern/modules`: Managing all command modules -> [ModuleManager](../../api/interfaces/ModuleManager)
>  - `@sern/emitter`: is the key to emit events and occurences in a project -> [Emitter](../../api/interfaces/Emitter)


Lets try to access the client you provided.

```ts title="src/commands/ping.ts"
import { Service } from '@sern/handler'

export default commandModule({ 
   // ...
    execute: (ctx) => {
        //Client!
        const client = Service('@sern/client');
    }
   // 
})

```
## Safety 
- Services can only be used after sern has made dependencies. 
    - Calling a service before will crash your application. 
- Services can be safely used outside of commandModules.
    - Be careful to not cause too many side effects.


## Related api 
- use `Service` for single dependency.
- use `Services` for multiple dependencies.



