--- updatedAt: 2026-06-12T07:54:27.000Z agentTools: projectIndex: https://api-docs.omnisend.com/llms.txt --- # How to send an SMS campaign ## Intro Send promotional text messages — flash sales, limited-time offers, event reminders — to your subscriber audience through the Campaigns API. SMS campaigns target specific segments or all subscribers and can be sent immediately or scheduled for a future time. See API reference: [Campaigns](https://api-docs.omnisend.com/v2026-03-15/reference/campaigns) | [Images](https://api-docs.omnisend.com/v2026-03-15/reference/images) ## Prerequisites * An API key with `campaigns.write` scope, or an OAuth token with the same scope * SMS channel enabled for your brand ([enable in Channel Settings → SMS](https://support.omnisend.com/en/articles/3283498-omnisend-sms)) * Sufficient SMS credits for your audience size ([manage credits](https://support.omnisend.com/en/articles/1832295-manage-your-omnisend-sms-credits-subscription)) — each sent message consumes credits based on the recipient's country ## Step 1: Create the campaign Create a draft SMS campaign with the message body and compliance text. The compliance fields are required — `stopKeywordText` is appended for US/CA recipients, and `unsubscribeLinkText` (which must contain `[[unsubscribe_link]]`) is appended for all other regions. See endpoint: [Create campaign](https://api-docs.omnisend.com/v2026-03-15/reference/post_campaigns) ```sh curl -X POST 'https://api.omnisend.com/api/campaigns' \ -H 'Authorization: Omnisend-API-Key YOUR-API-KEY' \ -H 'Omnisend-Version: 2026-03-15' \ -H 'Content-Type: application/json' \ -d '{ "name": "Summer Flash Sale", "type": "regular", "channel": "sms", "language": "en_US", "content": { "sms": { "message": "Flash sale! 30% off everything today only. Shop now: https://example.com/sale", "compliance": { "stopKeywordText": "Reply STOP to opt out", "unsubscribeLinkText": "Unsubscribe: [[unsubscribe_link]]" } } }, "audience": { "includedSegmentIDs": ["segment-id-1"] }, "sendingSettings": { "strategy": "scheduled", "scheduledAt": "2026-06-15T14:00:00Z" } }' ``` The response returns the campaign in `draft` status with an `id` you will use in subsequent steps. > **Note**: `audience` and `sendingSettings` are optional. Omitting `audience` (or leaving `includedSegmentIDs` empty) targets all subscribers. Omitting `sendingSettings` defaults to `immediate` strategy. Included and excluded segment IDs must not overlap. > **Note**: The total message length — body + compliance text + unsubscribe link — must not exceed 9 SMS segments. Links in the message body are auto-shortened by default (`isLinkShorteningEnabled: true`). ## Step 2: Send the campaign Trigger the campaign send. If the sending strategy is `immediate` (the default), the campaign starts sending right away. If `scheduled`, it queues for the scheduled time. See endpoint: [Send campaign](https://api-docs.omnisend.com/v2026-03-15/reference/post_campaigns-id-send) ```sh curl -X POST 'https://api.omnisend.com/api/campaigns/CAMPAIGN_ID/send' \ -H 'Authorization: Omnisend-API-Key YOUR-API-KEY' \ -H 'Omnisend-Version: 2026-03-15' ``` A `204` response confirms the send was initiated. The campaign status changes to `started` (immediate) or `scheduled` (scheduled strategy). > **Warning**: The send endpoint returns `402 Payment Required` when the campaign audience exceeds your current [billing tier](https://support.omnisend.com/en/articles/3533018-omnisend-pricing-plans) limits or you have insufficient SMS credits. A plan upgrade or credit purchase is required to proceed. ## Verify results Retrieve the campaign to check its current status. See endpoint: [Get campaign](https://api-docs.omnisend.com/v2026-03-15/reference/get_campaigns-id) ```sh curl -X GET 'https://api.omnisend.com/api/campaigns/CAMPAIGN_ID' \ -H 'Authorization: Omnisend-API-Key YOUR-API-KEY' \ -H 'Omnisend-Version: 2026-03-15' ``` | **Status** | **Meaning** | | ---------- | -------------------------------------------------------------- | | scheduled | Campaign is queued to send at the scheduled time | | started | Campaign is actively sending | | paused | Campaign is undergoing automated verification (\~60 min check) | | sent | Campaign has finished sending | | onHold | Campaign did not pass content verification — review required | | error | Campaign encountered an error during sending | ## Optional: Add an image (MMS) To send MMS (image + text) to US/CA recipients instead of plain SMS, upload an image via the Images API and reference it in the campaign content. Recipients in other regions always receive plain SMS without the image. ### Upload the image Upload from a public URL. The image must be JPEG, PNG, or GIF and must not exceed 500 KB. Images wider than 2000 px are automatically resized. See endpoint: [Upload image by URL](https://api-docs.omnisend.com/v2026-03-15/reference/post_images) ```sh curl -X POST 'https://api.omnisend.com/api/images' \ -H 'Authorization: Omnisend-API-Key YOUR-API-KEY' \ -H 'Omnisend-Version: 2026-03-15' \ -H 'Content-Type: application/json' \ -d '{ "url": "https://your-cdn.com/promo-banner.jpg", "name": "summer-sale-mms" }' ``` The response returns an `id` field — use it as `imageID` when creating the campaign. > **Note**: The URL must point to a publicly accessible image (JPEG, PNG, or GIF). Your API key needs the additional `images.write` scope for this call. For all upload options see [Images API reference](https://api-docs.omnisend.com/v2026-03-15/reference/images). ### Create an MMS campaign Include `imageID` in the SMS content object. The rest of the payload is identical to a plain SMS campaign from [Step 1](#step-1-create-the-campaign). See endpoint: [Create campaign](https://api-docs.omnisend.com/v2026-03-15/reference/post_campaigns) ```sh curl -X POST 'https://api.omnisend.com/api/campaigns' \ -H 'Authorization: Omnisend-API-Key YOUR-API-KEY' \ -H 'Omnisend-Version: 2026-03-15' \ -H 'Content-Type: application/json' \ -d '{ "name": "Summer Flash Sale (MMS)", "type": "regular", "channel": "sms", "language": "en_US", "content": { "sms": { "message": "Flash sale! 30% off everything today only.", "imageID": "IMAGE_ID", "compliance": { "stopKeywordText": "Reply STOP to opt out", "unsubscribeLinkText": "Unsubscribe: [[unsubscribe_link]]" } } }, "audience": { "includedSegmentIDs": ["segment-id-1"] }, "sendingSettings": { "strategy": "scheduled", "scheduledAt": "2026-06-15T14:00:00Z" } }' ``` > **Note**: US/CA recipients receive MMS (image + text). When `imageID` is set, the message limit for US/CA is 1600 characters (body + compliance text) instead of the usual 9 SMS segments. ## Troubleshooting * **409 Conflict on update or send**: Only campaigns in `draft` status can be edited or sent. If the campaign has already been sent or scheduled, [copy it](https://api-docs.omnisend.com/v2026-03-15/reference/post_campaigns-id-copy) to create a new draft. * **402 Payment Required on send**: The campaign audience exceeds your plan limits or you have insufficient SMS credits. Upgrade your plan or purchase credits. * **Validation error on `compliance.unsubscribeLinkText`**: The value must contain the `[[unsubscribe_link]]` placeholder. Example: `"Unsubscribe: [[unsubscribe_link]]"`. * **Campaign ends in `error` status**: A campaign can fail during sending due to insufficient SMS credits or internal issues. The API does not always include error details in the campaign response — check your [SMS credit balance](https://support.omnisend.com/en/articles/1832295-manage-your-omnisend-sms-credits-subscription) if the cause is unclear. * **Message too long**: The total message (body + compliance + unsubscribe link) must fit within 9 SMS segments. For MMS to US/CA, the limit is 1600 characters. Shorten your message or compliance text. ## Related resources * [Campaigns API reference](https://api-docs.omnisend.com/v2026-03-15/reference/campaigns) * [Images API reference](https://api-docs.omnisend.com/v2026-03-15/reference/images) * [How to send an email campaign](https://api-docs.omnisend.com/v2026-03-15/docs/how-to-send-email-campaign) * [SMS campaigns (Help Center)](https://support.omnisend.com/en/articles/3283498-omnisend-sms) * [Manage SMS credits & subscription (Help Center)](https://support.omnisend.com/en/articles/1832295-manage-your-omnisend-sms-credits-subscription) * [Omnisend pricing plans (Help Center)](https://support.omnisend.com/en/articles/3533018-omnisend-pricing-plans)