# Start a campaign

> Starts sending a draft campaign, or resumes a paused one. Messages go out one at a time, send_interval_seconds apart.

Source: https://www.bloomtext.com/developers/api/reference/start-campaign/

`POST /campaigns/{campaignId}/start`

Starts sending a draft campaign, or resumes a paused one. Messages go out one at a time, `send_interval_seconds` apart.

**Credentials:** [API key](https://www.bloomtext.com/developers/api/api-keys/) or an [org admin’s OAuth token](https://www.bloomtext.com/developers/api/oauth/) · **Scope:** `messages.write` · **Idempotent:** With `Idempotency-Key`

### Path parameters

- `campaignId` (UUID, required): ID of the campaign.

### Headers

- `Idempotency-Key` (UUID, required): A UUID you generate for each write. Retrying with the same key returns the original result for 24 hours. Reusing a key with a different method, path, or body returns 409.

### Returns

Returns `200 OK` with the [Campaign object](https://www.bloomtext.com/developers/api/reference/campaign-object/).

### Errors

Failed requests return `application/problem+json` [problem details](https://www.bloomtext.com/developers/api/errors/). The errors specific to this endpoint:

| Status | Code | Meaning |
| --- | --- | --- |
| 400 | `invalid_request` | The request is malformed, such as invalid JSON. |
| 401 | `invalid_token` | The API key or access token is missing, expired, or revoked. |
| 403 | `insufficient_scope` | The credential doesn’t have the scope this endpoint needs. |
| 404 | `not_found` | The resource doesn’t exist, or isn’t visible to this credential. |
| 409 | `idempotency_key_reused` | The Idempotency-Key was already used with a different request. |
| 409 | `idempotency_request_in_progress` | A request with this Idempotency-Key is still running. Retry shortly. |
| 409 | `campaign_not_startable` | The campaign is already running, completed, stopped, or archived. |
| 422 | `campaign_empty` | The campaign has no recipients waiting to be sent. |
| 429 | `rate_limited` | Too many requests. Retry after `Retry-After` seconds. |

```bash filename="Request"
curl -X POST "https://api.bloomtext.com/v1/campaigns/c4a7e2d1-9b3f-4e6a-8d2c-1f0e9b8a7c65/start" \
  -H "Authorization: Bearer $BLOOMTEXT_API_KEY" \
  -H "Idempotency-Key: $(uuidgen)"
```

```js filename="Request"
const response = await fetch('https://api.bloomtext.com/v1/campaigns/c4a7e2d1-9b3f-4e6a-8d2c-1f0e9b8a7c65/start', {
  method: 'POST',
  headers: {
    Authorization: `Bearer ${process.env.BLOOMTEXT_API_KEY}`,
    'Idempotency-Key': crypto.randomUUID(),
  },
})

if (!response.ok) throw new Error(`BloomText API error: ${response.status}`)
const data = await response.json()
```

```python filename="Request"
import os
import uuid

import requests

response = requests.post(
    "https://api.bloomtext.com/v1/campaigns/c4a7e2d1-9b3f-4e6a-8d2c-1f0e9b8a7c65/start",
    headers={
        "Authorization": f"Bearer {os.environ['BLOOMTEXT_API_KEY']}",
        "Idempotency-Key": str(uuid.uuid4()),
    },
)
response.raise_for_status()
data = response.json()
```

```go filename="Request"
package main

import (
	"fmt"
	"io"
	"net/http"
	"os"

	"github.com/google/uuid"
)

func main() {
	req, err := http.NewRequest("POST", "https://api.bloomtext.com/v1/campaigns/c4a7e2d1-9b3f-4e6a-8d2c-1f0e9b8a7c65/start", nil)
	if err != nil {
		panic(err)
	}
	req.Header.Set("Authorization", "Bearer "+os.Getenv("BLOOMTEXT_API_KEY"))
	req.Header.Set("Idempotency-Key", uuid.NewString())

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()

	out, _ := io.ReadAll(res.Body)
	fmt.Println(res.Status, string(out))
}
```

```ruby filename="Request"
require "net/http"
require "json"
require "securerandom"

uri = URI("https://api.bloomtext.com/v1/campaigns/c4a7e2d1-9b3f-4e6a-8d2c-1f0e9b8a7c65/start")
request = Net::HTTP::Post.new(uri)
request["Authorization"] = "Bearer #{ENV.fetch("BLOOMTEXT_API_KEY")}"
request["Idempotency-Key"] = SecureRandom.uuid

response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) do |http|
  http.request(request)
end
data = JSON.parse(response.body)
```

```json filename="Response · 200 OK"
{
  "id": "c4a7e2d1-9b3f-4e6a-8d2c-1f0e9b8a7c65",
  "name": "Flu shot reminders, October",
  "status": "running",
  "channel": "secure",
  "body": "Flu shots are available at Example Clinic. Reply here to book a time.",
  "phone_number": {
    "number": "+15125550100",
    "team": "Front desk"
  },
  "sender": {
    "id": "b7e1c3a9-4d2f-4a8b-9c6e-0f1d2e3a4b5c",
    "name": "Reminder service",
    "kind": "api_key"
  },
  "send_interval_seconds": 1,
  "counts": {
    "recipients": 412,
    "pending": 148,
    "sent": 264,
    "delivered": 251,
    "failed": 6,
    "skipped": 0
  },
  "archived": false,
  "created_at": "2026-09-21T15:04:05Z",
  "started_at": "2026-09-21T15:05:00Z",
  "finished_at": null
}
```