# IDistributedApplicationBuilder.addConnectionString

- Module: [Aspire.Hosting](/reference/api/typescript/aspire.hosting.md)
- Defined on: [IDistributedApplicationBuilder](/reference/api/typescript/aspire.hosting/idistributedapplicationbuilder.md)
- Version: `13.4.0`
- Kind: `method`

Adds a connection string resource

## Definition

```typescript
interface IDistributedApplicationBuilder {
  // ... omitted for brevity
  addConnectionString(
      name: string,
      environmentVariableNameOrExpression?: ReferenceExpression): IResourceWithConnectionString;
}
```

## Signature

```typescript
addConnectionString(
    name: string,
    environmentVariableNameOrExpression?: ReferenceExpression): IResourceWithConnectionString
```

## Parameters

- `name` (`string`)
- `environmentVariableNameOrExpression` ([ReferenceExpression](/reference/api/typescript/aspire.hosting/referenceexpression.md)) `optional`

## Returns

[IResourceWithConnectionString](/reference/api/typescript/aspire.hosting/iresourcewithconnectionstring.md) `builder`

## Defined on

- [IDistributedApplicationBuilder](/reference/api/typescript/aspire.hosting/idistributedapplicationbuilder.md) -- `interface`