> ## Documentation Index > Fetch the complete documentation index at: https://loops.so/docs/llms.txt > Use this file to discover all available pages before exploring further. # API Changelog > Release notes for the Loops REST API and webhooks, covering new endpoints, fields, breaking changes, and deprecations across OpenAPI versions. **October 20, 2026** New: workflows can now be moved between groups in the [Update workflow](https://loops.so/docs/api-reference/update-workflow.md) endpoint. **October 6, 2026** New: endpoints for managing workflow groups. **September 30, 2026** Updated: campaigns created without a group are now added to the "Unsorted" group rather than the first group listed in your account. **September 29, 2026** New: metrics endpoints for [campaigns](https://loops.so/docs/api-reference/get-campaign-metrics.md), [transactional emails](https://loops.so/docs/api-reference/get-transactional-email-metrics.md), and [workflow email nodes](https://loops.so/docs/api-reference/get-workflow-node-metrics.md). **September 17, 2026** Updated: `ccEmail` and `bccEmail` are now rejected in the API when [updating campaign email messages](https://loops.so/docs/api-reference/update-email-message.md), matching app behavior (they are still accepted for workflow and transactional emails). **September 1, 2026** New: [Delete a workflow](https://loops.so/docs/api-reference/delete-workflow.md) endpoint. **August 31, 2026** New: campaign, transactional and workflow endpoints now include a `url` field, which gives quick access to the object in the Loops app. **July 23, 2026** New: * [Create audience segment](https://loops.so/docs/api-reference/create-audience-segment.md) endpoint. * Endpoints for creating and editing [workflows](https://loops.so/docs/api-reference/intro.md#workflows) and [workflow nodes](https://loops.so/docs/api-reference/intro.md#workflow-nodes). * Endpoints for reading [event patterns](https://loops.so/docs/api-reference/intro.md#event-patterns). Updated: removed `queuedContactLimitReached` from workflow node delete and mailing list change responses. **July 16, 2026** Updated: `rootNodeId` is now always a non-null string in [workflow](https://loops.so/docs/api-reference/get-workflow.md) responses. **July 8, 2026** New: endpoints for creating and updating themes and components. **July 2, 2026** New: [Guardian](https://loops.so/docs/api-reference/run-guardian-checks.md) endpoint for validating email message content via the API. **July 1, 2026** New: a `transactionalName` field in the [transactional.email.sent](https://loops.so/docs/webhooks.md#transactional-email-sent) webhook event. **June 22, 2026** New: endpoints for viewing [workflows](https://loops.so/docs/api-reference/list-workflows.md) and [workflow nodes](https://loops.so/docs/api-reference/get-workflow-node.md). These endpoints are currently in open alpha. **June 19, 2026** New: endpoints for [campaign groups](https://loops.so/docs/api-reference/list-campaign-groups.md), [transactional groups](https://loops.so/docs/api-reference/list-transactional-groups.md), [audience segments](https://loops.so/docs/api-reference/list-audience-segments.md), and [email message previews](https://loops.so/docs/api-reference/preview-email-message.md). Updated: * [Campaign](https://loops.so/docs/api-reference/create-campaign.md) endpoints now support audience targeting (mailing list, segment, or filter), groups, and scheduling. * [Email message](https://loops.so/docs/api-reference/update-email-message.md) endpoints now support CC/BCC, language, email format, and property fallbacks. * [Transactional email](https://loops.so/docs/api-reference/create-transactional-email.md) endpoints now support groups. **June 5, 2026** New: endpoints for creating and editing transactional emails. These endpoints are currently in an open alpha. **May 20, 2026** New: [Upload](https://loops.so/docs/api-reference/create-upload.md) endpoints for uploading images to use in emails. **April 24, 2026** New: endpoints for creating and editing campaigns. These endpoints are currently in an open alpha. **March 25, 2026** New: API endpoints to [check](https://loops.so/docs/api-reference/check-contact-suppression.md) and [remove](https://loops.so/docs/api-reference/remove-contact-suppression.md) suppression for contacts. **February 13, 2026** New: a `campaignName` field in the [campaign.email.sent](https://loops.so/docs/webhooks.md#campaign-email-sent) webhook event. **October 17, 2025** New: an [`email.resubscribed`](https://loops.so/docs/webhooks#email-resubscribed) webhook event for when contacts resubscribe to your marketing email from an email's "Unsubscribe" link. **October 13, 2025** New: an `optInStatus` field from [double opt-in](https://loops.so/docs/contacts/double-opt-in.md) in the [Find contact](https://loops.so/docs/api-reference/find-contact.md) endpoint and in `contact.created` [webhook events](https://loops.so/docs/webhooks.md). **September 29, 2025** New: [webhooks](https://loops.so/docs/webhooks.md) are now available to all users. **September 11, 2025** Improvement: all endpoints now return a `success` and `message` field in the error response bodies. `error` and `path` top-level keys are now deprecated but will continue to be supported for some time for backward compatibility. **August 21, 2025** The docs have been updated to reflect that the `email` parameter is optional in the [Update contact](https://loops.so/docs/api-reference/update-contact.md) endpoint if a `userId` is provided. **May 23, 2025** Improvement: data variables are now optional in the [Send transactional email](https://loops.so/docs/api-reference/send-transactional-email.md) endpoint. [Read more](https://loops.so/docs/transactional.md#optional-data-variables) **April 29, 2025** New: an `Idempotency-Key` header when [sending events](https://loops.so/docs/api-reference/send-event.md). **March 28, 2025** New: an `Idempotency-Key` header when [sending transactional emails](https://loops.so/docs/api-reference/send-transactional-email.md). **February 28, 2025** New: an endpoint for [listing transactional emails](https://loops.so/docs/api-reference/list-transactional-emails.md) and their data variables. **February 5, 2025** New: [webhooks](https://loops.so/docs/webhooks.md) are in Beta. **January 14, 2025** New: new endpoints for [creating contact properties](https://loops.so/docs/api-reference/create-contact-property.md) and [listing contact properties](https://loops.so/docs/api-reference/list-contact-properties.md). Deprecation: the [List custom fields](https://loops.so/docs/api-reference/list-custom-fields) endpoint is now deprecated in favor of the new [List contact properties](https://loops.so/docs/api-reference/list-contact-properties.md) endpoint. **December 18, 2024** New: we added `description` to mailing list objects in the [List mailing lists](https://loops.so/docs/api-reference/list-mailing-lists.md) endpoint. **November 5, 2024** Improvement: the maximum payload size for the transactional endpoint has been increased from 1MB to 4MB, allowing for more or larger attachments. **September 6, 2024** New: our new [Nuxt module](https://loops.so/docs/sdks/nuxt.md) is now out! **August 16, 2024** New: our new [Ruby SDK](https://loops.so/docs/sdks/ruby.md) is available! **August 15, 2024** New: we added an `isPublic` attribute to mailing list objects in the [List mailing lists](https://loops.so/docs/api-reference/list-mailing-lists.md) endpoint. **June 28, 2024** New: there's a new `addToAudience` parameter in the [Send transactional email](https://loops.so/docs/api-reference/send-transactional-email.md) endpoint that can add contacts to your audience. **June 18, 2024** New: support for our new [mailing lists](https://loops.so/docs/contacts/mailing-lists.md) feature. You can now add contacts to and remove contacts from mailing lists in the [Create contact](https://loops.so/docs/api-reference/create-contact.md), [Update contact](https://loops.so/docs/api-reference/update-contact.md) and [Send event](https://loops.so/docs/api-reference/send-event.md) endpoints. There is also a [new endpoint](https://loops.so/docs/api-reference/list-mailing-lists.md) for retrieving your mailing lists. **April 18, 2024** New: you can now [Find contacts](https://loops.so/docs/api-reference/find-contact.md) by `userId`. **April 9, 2024** New: a new endpoint for testing your integration and/or API key: [API key](https://loops.so/docs/api-reference/api-key.md). **March 21, 2024** New: you can now include [event properties](https://loops.so/docs/events/properties.md) in requests to the [Send event](https://loops.so/docs/api-reference/send-event.md) endpoint. **March 13, 2024** Improvement: we removed behavior that returned a `400 Bad Request` response if an unrecognized property was added to Contact endpoints. **February 9, 2024** Improvement: sending in a payload that contains an unrecognized property will now return a `400 Bad Request` response. **January 25, 2024** Clarification in the API docs that `userId` can be used in a [Send event](https://loops.so/docs/api-reference/send-event.md) request. **November 6, 2023** New: we added a new endpoint for [querying custom contact properties](https://loops.so/docs/api-reference/list-custom-fields). **October 30, 2023** Our [official JavaScript/TypeScript SDK](https://loops.so/docs/sdks/javascript.md) is now available! **October 12, 2023** New: we now accept dates as a custom [contact property](https://loops.so/docs/contacts/properties.md) type. [View the available formats](https://loops.so/docs/contacts/properties.md#dates). ## Related topics - [API Introduction](https://loops.so/docs/api-reference/intro.md) - [API key](https://loops.so/docs/api-reference/api-key.md) - [API Examples](https://loops.so/docs/api-reference/examples.md) - [Bubble API Connector](https://loops.so/docs/guides/bubble-api-connector.md) - [Campaigns API examples](https://loops.so/docs/api-reference/examples/campaigns.md)