---
title: "Send a campaign now"
method: POST
path: "/campaigns/{campaignId}/send"
tags: ["Campaigns"]
---

# Send a campaign now

`POST /campaigns/{campaignId}/send`

## Request

- Base URL: `https://app.lettr.com/api`
- URL: `https://app.lettr.com/api/campaigns/{campaignId}/send`
- Auth: HTTP bearer

Immediately dispatches a draft campaign. The campaign must be a draft with a subject, sender email, and content. Sending is asynchronous; the campaign transitions to `preparing`. Requires the `campaigns:write` scope. Not available to sandbox keys.

## Path parameters

- `campaignId` string, uuid, required

## Response `202`

Campaign sending started.

- CampaignActionResponse
  - `message` string, required
  - `data` CampaignSummary: Campaign summary with embedded engagement stats.
    - `id` string, uuid, required
    - `name` string, required
    - `subject` string, nullable: Email subject line
    - `from_email` string, email, nullable: Sender email address
    - `from_name` string, nullable: Sender display name
    - `reply_to` string, email, nullable: Reply-to address
    - `status` 'draft' | 'scheduled' | 'preparing' | 'in_review' | 'sending' | 'sent' | 'failed', required
    - `scheduled_at` string, date-time, nullable: Scheduled delivery time (ISO 8601)
    - `total_recipients` integer, nullable: Total recipients resolved for the send
    - `sent_count` integer, required
    - `sent_at` string, date-time, nullable: When the campaign finished sending (ISO 8601)
    - `created_at` string, date-time, required
    - `stats` CampaignStats, required: Aggregated engagement statistics for a campaign.
      - `injections` integer, required
      - `deliveries` integer, required
      - `bounces` integer, required
      - `spam_complaints` integer, required
      - `opens` integer, required
      - `unique_opens` integer, required
      - `clicks` integer, required
      - `unique_clicks` integer, required
      - `unsubscribes` integer, required

## Other responses

- `401`: Unauthorized - Missing or invalid API key
- `403`: Forbidden - API key does not have the required scope
- `404`: Resource not found
- `422`: Precondition failed. `campaign_not_sendable` when the campaign is not a draft or is missing a subject, sender, or content; `campaign_has_pending_schedule` when the campaign already has a future scheduled delivery time (unschedule it first to send now — this also clears a time staged on a draft — or use the schedule endpoint to confirm it).
- `500`: Internal server error
- `503`: Service unavailable - the API key could not be verified, so the request was not processed. This does not mean the key is invalid; retry after the delay given in the Retry-After header.

---

[API](https://skmtc.dev/lettr/apis/lettr-api.md) · [All operations](https://skmtc.dev/lettr/apis/lettr-api/llms.txt) · [OpenAPI document](https://skmtc.dev/lettr/apis/lettr-api/revisions/48ef0dac1ebd?raw)