> For the complete documentation index, see [llms.txt](https://docs.mailtrap.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mailtrap.io/developers/email-marketing/email-campaigns/update-an-email-campaign.md).

# Update an email campaign

Updates an existing `draft` campaign. Only the provided attributes are changed. To edit the template (subject or design), pass `template_attributes` — the campaign's template is always edited in place, and only the template sub-fields you provide change (see the `template_attributes` schema for the partial-update rules).

Update accepts the same fields as create, including the audience (`contact_list_ids`/`contact_segment_ids`). The typical flow is to create a draft, add its design and audience over one or more updates, then schedule or start it via the dedicated `schedule`/`start` action endpoints.

Only `draft` campaigns can be updated — editing a campaign that is already scheduled/sending returns `422`.

```json
{"openapi":"3.1.0","info":{"title":"Email Campaigns","version":"2.0.0"},"tags":[{"name":"Email Campaigns","description":"Manage email campaigns"}],"servers":[{"description":"Mailtrap API","url":"https://mailtrap.io"}],"security":[{"HeaderAuth":[]},{"BearerAuth":[]}],"components":{"securitySchemes":{"HeaderAuth":{"type":"apiKey","description":"Pass the API token in the Api-Token header","in":"header","name":"Api-Token"},"BearerAuth":{"type":"http","description":"Pass the API token as a Bearer token in the Authorization header","scheme":"bearer"}},"parameters":{"email_campaign_id":{"name":"email_campaign_id","description":"Unique identifier of the email campaign","in":"path","required":true,"schema":{"type":"integer","format":"int64","minimum":1}}},"schemas":{"EmailCampaignUpdateRequest":{"description":"Attributes to update. All fields optional; only provided fields change.","allOf":[{"$ref":"#/components/schemas/EmailCampaignWritableAttributes"}]},"EmailCampaignWritableAttributes":{"type":"object","description":"Campaign attributes. Both create and update accept the same fields. Create and update only\nmanage attributes and audience — the campaign always stays in `draft`; scheduling and\nstarting are performed via the dedicated lifecycle action endpoints.","properties":{"name":{"type":"string","description":"Campaign name."},"domain_id":{"type":"integer","format":"int64","description":"ID of the verified sending domain used for the campaign, as returned by the Sending Domains endpoints."},"from_display_name":{"type":"string","description":"Display name shown in the From header."},"from_local_part":{"type":"string","description":"Local part (before the @) of the From address."},"reply_to":{"$ref":"#/components/schemas/ReplyTo"},"template_attributes":{"$ref":"#/components/schemas/TemplateAttributes"},"delivery_mode":{"type":"string","description":"How the campaign is delivered. `rapid` sends as fast as possible; `gradual` throttles\nsending to `delivery_options.emails_per_hour`.","enum":["rapid","gradual"]},"delivery_options":{"type":"object","description":"Delivery throttling options. Applies when `delivery_mode` is `gradual`.","properties":{"emails_per_hour":{"type":["integer","null"]}}},"contact_list_ids":{"type":"array","description":"IDs of contact lists to send to. Treated as the full set of included lists — lists not\nlisted are removed. Combine with `contact_segment_ids` to target both.","items":{"type":"integer","format":"int64"}},"contact_segment_ids":{"type":"array","description":"IDs of contact segments to send to. Treated as the full set of included segments.","items":{"type":"integer","format":"int64"}}}},"ReplyTo":{"type":"object","description":"Reply-To address parts.","properties":{"display_name":{"type":"string"},"local_part":{"type":"string"},"domain":{"type":"string"}}},"TemplateAttributes":{"type":"object","description":"Inline email template — the campaign's subject and design. Each campaign has exactly\none template, created together with it using the `template_attributes` fields.\nOn update, the campaign's template is always edited in place.\nUpdates are partial: only the sub-fields you provide change; sub-fields that\nare omitted or sent as `null` keep their current value.","properties":{"subject":{"type":"string","maxLength":255,"description":"Email subject line. Required when creating a campaign.\nSupports merge tags, e.g. `Hi {{first_name}}`."},"body_html":{"type":"string","maxLength":10000000,"description":"HTML body of the email (the design). Optional for a draft; required before the\ncampaign can be scheduled or started. Include an unsubscribe link via an anchor\nwhose `href` contains the `__unsubscribe_url__` placeholder — a design without one\nis accepted, but flagged with an \"Unsubscribe link is missing\" warning in the\nMailtrap UI. Supports `{{tag_name}}` merge tags."},"body_text":{"type":["string","null"],"maxLength":10000000,"description":"Optional plain-text alternative of the email body. Supports the same\n`__unsubscribe_url__` placeholder and `{{tag_name}}` merge tags as `body_html`."},"merge_tags":{"type":"array","description":"Bare names of the merge tags referenced in the subject/body, without the `{{ }}`\ndelimiters — e.g. `[\"first_name\"]` when the content contains `{{first_name}}`.\nLets Mailtrap track which contact fields the campaign uses. Replaced as a whole\nwhen provided; defaults to an empty array.","items":{"type":"string"}}}},"EmailCampaign":{"type":"object","properties":{"id":{"type":"integer","format":"int64"},"domain_id":{"type":"integer","format":"int64","description":"ID of the sending domain used for the campaign, as returned by the Sending Domains endpoints."},"domain_name":{"type":"string"},"name":{"type":"string"},"from_local_part":{"type":"string"},"from_display_name":{"type":"string"},"reply_to":{"$ref":"#/components/schemas/ReplyTo"},"current_state":{"type":"string","description":"Current state of the campaign in its lifecycle.","enum":["draft","scheduled","started","queued","paused","terminating","under_review","finished","failed","failed_immediately"]},"current_state_metadata":{"type":"object","description":"Metadata about the most recent state transition. Which keys are present depends on the state.","properties":{"reason":{"type":"string"},"error":{"type":"string","description":"Last error message recorded for a failed campaign."},"errors":{"type":"array","description":"Per-recipient errors recorded when sending failed.","items":{"type":"object","properties":{"message":{"type":"string"},"rcpt_index":{"type":"integer"}}}},"scheduled_at":{"type":"string","format":"date-time","description":"When the campaign is scheduled to send (ISO 8601). Present in the `scheduled` state."}}},"created_at":{"type":"string","format":"date-time"},"updated_at":{"type":"string","format":"date-time"},"last_started_at":{"type":["string","null"],"format":"date-time"},"last_started_at_date":{"type":"string","format":"date","description":"Date the campaign was last started. Present only when the campaign has been started."},"recipient_total_count":{"type":["integer","null"],"description":"Total number of recipients targeted by the campaign. `null` until the audience is resolved."},"contact_list_ids":{"type":"array","description":"IDs of the contact lists included in the campaign's audience.","items":{"type":"integer","format":"int64"}},"contact_segment_ids":{"type":"array","description":"IDs of the contact segments included in the campaign's audience.","items":{"type":"integer","format":"int64"}},"delivery_mode":{"type":"string","description":"How the campaign is delivered. `rapid` sends as fast as possible; `gradual` throttles\nsending to `delivery_options.emails_per_hour`.","enum":["rapid","gradual"]},"delivery_options":{"type":"object","description":"Delivery throttling options. Applies when `delivery_mode` is `gradual`.","properties":{"emails_per_hour":{"type":["integer","null"]}}},"template":{"type":"object","description":"The campaign's template. `body_html` and `body_text` are returned only on\nsingle-campaign responses (create, update, get-by-ID); the list endpoint omits them to\nkeep the payload small.","properties":{"id":{"type":"integer","format":"int64"},"subject":{"type":"string"},"merge_tags":{"type":"array","items":{"type":"string"}},"body_html":{"type":["string","null"],"description":"HTML body (the design). Returned only on single-campaign responses."},"body_text":{"type":["string","null"],"description":"Plain-text body. Returned only on single-campaign responses."}}}}},"UnauthenticatedResponse":{"type":"object","properties":{"error":{"type":"string"}}},"PermissionDeniedResponse":{"type":"object","properties":{"errors":{"type":"string"}}},"NotFoundResponse":{"type":"object","properties":{"error":{"type":"string"}}},"ValidationErrorResponse":{"type":"object","properties":{"errors":{"type":"object","additionalProperties":{"type":"array","items":{"type":"string"}}}}},"RateLimitedResponse":{"type":"object","properties":{"error":{"type":"string"}}}},"responses":{"EmailCampaignResponse":{"description":"A single email campaign.","content":{"application/json":{"schema":{"type":"object","properties":{"data":{"$ref":"#/components/schemas/EmailCampaign"}}}}}},"UNAUTHENTICATED":{"description":"Authentication failed — missing or invalid API token.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/UnauthenticatedResponse"}}}},"PERMISSION_DENIED":{"description":"The API token does not have permission to access this resource.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/PermissionDeniedResponse"}}}},"NOT_FOUND":{"description":"The requested email campaign was not found.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/NotFoundResponse"}}}},"VALIDATION_ERROR":{"description":"The request was rejected due to validation errors.","content":{"application/json":{"schema":{"$ref":"#/components/schemas/ValidationErrorResponse"}}}},"RATE_LIMITED":{"description":"Too many requests. The public API is rate limited to 150 requests per 10 seconds per\nAPI token. Retry after the window resets (see the `x-ratelimit-reset` header).","headers":{},"content":{"application/json":{"schema":{"$ref":"#/components/schemas/RateLimitedResponse"}}}}}},"paths":{"/api/email_campaigns/{email_campaign_id}":{"patch":{"operationId":"updateEmailCampaign","summary":"Update an email campaign","description":"Updates an existing `draft` campaign. Only the provided attributes are changed. To edit the\ntemplate (subject or design), pass `template_attributes` — the campaign's template is\nalways edited in place, and only the template sub-fields you provide change (see the\n`template_attributes` schema for the partial-update rules).\n\nUpdate accepts the same fields as create, including the audience\n(`contact_list_ids`/`contact_segment_ids`). The typical flow is to create a draft, add its\ndesign and audience over one or more updates, then schedule or start it via the dedicated\n`schedule`/`start` action endpoints.\n\nOnly `draft` campaigns can be updated — editing a campaign that is already scheduled/sending\nreturns `422`.","tags":["Email Campaigns"],"parameters":[{"$ref":"#/components/parameters/email_campaign_id"}],"requestBody":{"required":true,"content":{"application/json":{"schema":{"$ref":"#/components/schemas/EmailCampaignUpdateRequest"}}}},"responses":{"200":{"$ref":"#/components/responses/EmailCampaignResponse"},"401":{"$ref":"#/components/responses/UNAUTHENTICATED"},"403":{"$ref":"#/components/responses/PERMISSION_DENIED"},"404":{"$ref":"#/components/responses/NOT_FOUND"},"422":{"$ref":"#/components/responses/VALIDATION_ERROR"},"429":{"$ref":"#/components/responses/RATE_LIMITED"}}}}}}
```


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