The universal API for sending emails.
The universal API for sending emails. On Nagent, Resend is exposed as a fully-configurable email integration that any agent can call — 62 actions, and API key authentication. No code is required to wire Resend into your workflow — connect it once via the External Integrations panel and reuse it across every agent you build.
Agent builders use Resend to automate the kinds of tasks email teams previously handled manually. Concrete examples — each one is a single agent step in Nagent — include:
Every action and trigger is paired with a structured input/output schema (visible in the sections below), so when you wire Resend into Helix — our agentic agent builder — the editor knows exactly what each step expects and produces. Configure once, deploy anywhere across your Nagent agents.
Every operation an agent can call against Resend, with input parameters and output schema. Drop these into any step of an agent built in Helix.
RESEND_ADD_CONTACT_TO_SEGMENTAdd an existing contact to a segment in Resend. Use when you need to organize contacts into specific segments for targeted communication.
Input parameters
The ID of the contact to add to the segment.
The ID of the segment to add the contact to.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_CANCEL_EMAILCancel a scheduled email.
Input parameters
The id of the email to cancel.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_CREATE_API_KEYCreate a new API key to authenticate communications with Resend. Use when you need to generate a new authentication token for API access.
Input parameters
The API key name. Maximum 50 characters.
Restrict an API key to send emails only from a specific domain. Only used when the permission is 'sending_access'.
API key permission levels.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_CREATE_AUDIENCECreate a list of contacts.
Input parameters
The name of the audience you want to create.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_CREATE_CONTACTCreate a contact in Resend.
Input parameters
The email address of the contact. Must be a valid RFC-compliant email address.
The last name of the contact.
The first name of the contact.
The Audience ID.
The subscription status.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_CREATE_CONTACT_PROPERTYTool to create a new contact property in Resend. Use when you need to define custom fields for contacts.
Input parameters
The key of the contact property. Must be alphanumeric and underscore only, max 50 characters. Case sensitive.
The type of the contact property.
The fallback value for the property. Must match the type of the property.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_CREATE_CONTACT_V2Tool to create a new contact in Resend. Use when you need to add a contact to Resend without specifying an audience.
Input parameters
The email address of the contact.
List of topic subscriptions with ID and subscription status (opt_in or opt_out).
List of segment IDs to enroll the contact in.
The last name of the contact.
The first name of the contact.
Custom key-value pairs for the contact. Each property must have a key and value.
Contact's global subscription status; when true, the contact opts out of all broadcasts.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_CREATE_DOMAINCreate a domain through the Resend Email API. The domain is created in a pending/unverified state and cannot be used for sending emails until DNS verification is completed.
Input parameters
The name of the domain to be created.
The region where emails will be sent from. Supported values: 'us-east-1', 'eu-west-1', 'sa-east-1'. Unsupported values cause validation errors.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_CREATE_TEMPLATETool to create a new email template in Resend. Use when you need to define reusable email templates with optional variables.
Input parameters
Sender email address. To include a friendly name, use the format 'Your Name <sender@domain.com>'.
The HTML version of the template. Use {{VARIABLE_NAME}} syntax to reference template variables.
The name of the template.
The plain text version of the template. If omitted, Resend will auto-generate from HTML.
The alias of the template. This is an optional identifier that can be used instead of the template ID.
Email subject for the template.
Reply-to email address. For multiple addresses, send as an array of strings.
Template variables. Up to 50 variables can be defined per template.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_CREATE_TOPICTool to create a new topic to segment your audience. Use when you need to create a topic for organizing contacts by interests or preferences.
Input parameters
The topic name. Max length is 50 characters.
Topic visibility on the unsubscribe page.
The topic description. Max length is 200 characters.
The default subscription preference for new contacts. Accepts opt_in or opt_out. This value cannot be modified afterwards.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_CREATE_WEBHOOKTool to create a webhook to receive real-time notifications about email events. Use when you need to set up automated notifications for email status changes.
Input parameters
Array of event types to subscribe to. Common events include: 'email.sent', 'email.delivered', 'email.delivery_delayed', 'email.complained', 'email.bounced', 'email.opened', 'email.clicked'. Must include at least one event.
The URL where webhook events will be sent. Must be a valid HTTPS endpoint.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_DELETE_API_KEYRemove an existing API key from Resend. Use when you need to revoke or delete an API key.
Input parameters
The API key ID to delete.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_DELETE_AUDIENCERemove an existing audience.
Input parameters
The ID of the audience to delete.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_DELETE_CONTACTDelete a contact in Resend.
Input parameters
The Contact ID. Either id or email must be provided.
The Contact email. Either id or email must be provided.
The Audience ID.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_DELETE_CONTACT_BY_IDTool to remove an existing contact by its ID. Use when you need to delete a contact directly without specifying an audience.
Input parameters
The Contact ID to delete.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_DELETE_CONTACT_PROPERTYRemove an existing contact property from Resend.
Input parameters
The Contact Property ID.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_DELETE_DOMAINDelete a domain through the Resend Email API. Deletion is irreversible; ensure no active email traffic or DNS configurations depend on the domain before calling.
Input parameters
The id of the domain to delete.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_DELETE_SEGMENTRemove an existing segment. Use when you need to permanently delete a segment by its ID.
Input parameters
The ID of the segment to delete.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_DELETE_TEMPLATERemove an existing template. Use this action when you need to delete a template from Resend.
Input parameters
The Template ID or alias.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_DELETE_TOPICTool to remove an existing topic in Resend. Use when you need to delete a topic.
Input parameters
The Topic ID.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_DELETE_WEBHOOKRemove an existing webhook. Use this to delete a webhook configuration when you no longer need to receive event notifications at that endpoint.
Input parameters
The Webhook ID.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_DUPLICATE_TEMPLATEDuplicate an existing template through the Resend Email API. Use when you need to create a copy of an existing template.
Input parameters
The Template ID or alias to duplicate.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_GET_CONTACTTool to retrieve a single contact from Resend by ID or email. Use when you need to get details of a specific contact using the global contacts endpoint.
Input parameters
The Contact ID or email address to retrieve. Can be either a UUID (e.g., 'e169aa45-1ecf-4183-9955-b1499d5701d3') or an email address (e.g., 'user@example.com').
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_GET_CONTACT_PROPERTYTool to retrieve a single contact property from Resend. Use when you need to get details about a specific contact property by its ID.
Input parameters
The Contact Property ID.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_GET_EMAIL_ATTACHMENTRetrieve a single attachment from a sent email. Use when you need to access attachment metadata and download URL.
Input parameters
The ID of the email.
The ID of the attachment.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_GET_SEGMENTRetrieve a single segment by its ID. Use when you need to get detailed information about a specific segment.
Input parameters
The ID of the segment to retrieve.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_GET_TEMPLATERetrieve a single template by ID or alias from Resend. Use when you need to view template details.
Input parameters
The Template ID or alias to retrieve.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_GET_TOPICTool to retrieve a single topic by its ID in Resend. Use when you need to fetch details of a specific topic.
Input parameters
The Topic ID.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_GET_WEBHOOKRetrieve a single webhook for the authenticated user. Use this to get details about a specific webhook configuration including its endpoint, subscribed events, and signing secret.
Input parameters
The Webhook ID.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_ALL_CONTACTSTool to retrieve a list of all contacts from Resend. Use when you need to fetch contacts across all audiences with optional pagination.
Input parameters
Pagination cursor - retrieves contacts after this ID (the ID itself is excluded). Cannot be used with 'before' parameter.
Number of contacts to retrieve per request. Minimum 1, maximum 100. If not provided, defaults to 20.
Pagination cursor - retrieves contacts before this ID (the ID itself is excluded). Cannot be used with 'after' parameter.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_API_KEYSTool to retrieve a list of API keys for the authenticated user. Use when you need to view all API keys associated with the account, including pagination support for large result sets.
Input parameters
The ID after which we'll retrieve more API keys (for pagination). This ID will not be included in the returned list. Cannot be used with the 'before' parameter.
Number of API keys to retrieve. If omitted, all keys are returned in a single response.
The ID before which we'll retrieve more API keys (for pagination). This ID will not be included in the returned list. Cannot be used with the 'after' parameter.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_AUDIENCESList all audiences.
Input parameters
Cursor ID for forward pagination.
Maximum number of results to return. Max: 100.
Cursor ID for backward pagination.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_BROADCASTSTool to retrieve a list of broadcasts. Use when you need to fetch all broadcasts or paginate through them.
Input parameters
The ID after which we'll retrieve more broadcasts (for pagination). This ID will not be included in the returned list. Cannot be used with the before parameter.
Number of broadcasts to retrieve. If not provided, all broadcasts will be returned.
The ID before which we'll retrieve more broadcasts (for pagination). This ID will not be included in the returned list. Cannot be used with the after parameter.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_CONTACT_PROPERTIESTool to retrieve a list of contact properties from Resend. Use when you need to view available contact property definitions.
Input parameters
Return items after this cursor.
Number of items to return.
Return items before this cursor.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_CONTACTSList contacts in Resend.
Input parameters
Cursor ID for forward pagination.
Maximum number of results to return. Max: 100.
Cursor ID for backward pagination.
The Audience ID.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_CONTACT_SEGMENTSRetrieve a list of segments that a contact is part of. Use when you need to determine which segments a specific contact belongs to.
Input parameters
The ID of the contact.
Cursor ID for forward pagination.
Maximum number of results to return. Max: 100.
Cursor ID for backward pagination.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_CONTACT_TOPICSRetrieve a list of topic subscriptions for a contact in Resend. Use when you need to check which topics a specific contact is subscribed to.
Input parameters
Cursor ID for forward pagination.
Maximum number of results to return. Max: 100.
Cursor ID for backward pagination.
The ID of the contact.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_DOMAINSList all domains. Use the returned domain IDs as inputs for tools like RESEND_VERIFY_DOMAIN that require a domain_id.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_EMAIL_ATTACHMENTSTool to retrieve a list of attachments from a sent email. Use when you need to get information about files attached to an email sent via Resend.
Input parameters
Pagination cursor to fetch results after this attachment ID. Cannot be used with 'before'.
Maximum number of attachments to return. Use for pagination.
Pagination cursor to fetch results before this attachment ID. Cannot be used with 'after'.
The ID of the email to retrieve attachments from.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_EMAILSTool to retrieve a list of emails sent by your team. Use when you need to fetch outbound emails from your account. Supports pagination with limit, after, and before parameters.
Input parameters
Pagination cursor to fetch results after this email ID. Cannot be used with 'before'.
Maximum number of emails to return. Default 20, max 100, min 1.
Pagination cursor to fetch results before this email ID. Cannot be used with 'after'.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_RECEIVED_EMAILSTool to retrieve a list of received emails for the authenticated user. Use when you need to fetch incoming emails from the receiving endpoint.
Input parameters
Pagination cursor to fetch results after this email ID. Cannot be used with 'before'.
Maximum number of received emails to return.
Pagination cursor to fetch results before this email ID. Cannot be used with 'after'.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_SEGMENTSTool to retrieve a list of segments from Resend. Use when you need to view all available segments for audience management.
Input parameters
Return items after this cursor for pagination.
Number of items to return.
Return items before this cursor for pagination.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_TEMPLATESTool to retrieve a list of templates from Resend. Use when you need to get all available templates with optional pagination support.
Input parameters
Return items after this cursor.
Number of items to return.
Return items before this cursor.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_TOPICSTool to retrieve a list of topics for the authenticated user. Use when you need to fetch available topics with optional pagination support.
Input parameters
Return items after this cursor.
Number of items to return.
Return items before this cursor.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_LIST_WEBHOOKSRetrieve a list of webhooks for the authenticated user. Use this to view all configured webhooks with their endpoints, event types, and status.
Input parameters
Pagination cursor to fetch results after this webhook ID. Cannot be used with 'before'.
Maximum number of webhooks to return.
Pagination cursor to fetch results before this webhook ID. Cannot be used with 'after'.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_PUBLISH_TEMPLATEPublish a template through the Resend Email API. Use when you need to make a template publicly available.
Input parameters
The Template ID or alias to publish.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_REMOVE_CONTACT_FROM_SEGMENTRemove an existing contact from a segment. Use when you need to disassociate a contact from a specific segment.
Input parameters
The ID of the contact to remove from the segment.
The ID of the segment to remove the contact from.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_RETRIEVE_AUDIENCERetrieve a single audience.
Input parameters
The ID of the audience to retrieve.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_RETRIEVE_CONTACTRetrieve a contact in Resend.
Input parameters
The Contact ID.
The Audience ID.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_RETRIEVE_DOMAINRetrieve a single domain.
Input parameters
The id of the domain to retrieve.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_RETRIEVE_EMAILRetrieve a single email.
Input parameters
The id of the email to retrieve.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_SEND_BATCH_EMAILSTrigger up to 100 batch emails at once. Use when you need to send multiple emails in a single API request.
Input parameters
List of email items to send in batch. Maximum 100 emails per batch.
A unique identifier for the request to ensure emails are only sent once.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_SEND_EMAILSend an email using Resend. Confirm recipients and content with the user before invoking — sends are irreversible. All recipients must be listed explicitly via `to`, `cc`, or `bcc`; audience-based sending is unsupported. Render HTML or plain text externally before passing via `html` or `text`.
Input parameters
Cc recipient email address. For multiple addresses, send as an array of strings.
Recipient email address. For multiple addresses, send as an array of strings. Max 50.
Bcc recipient email address. For multiple addresses, send as an array of strings. Use `bcc` instead of `to` when sending to multiple recipients to prevent them from seeing each other's addresses.
Sender email address. To include a name, use the format 'Your Name <sender@domain.com>'.
The HTML version of the message. At least one of 'html' or 'text' must be provided.
The plain text version of the message. At least one of 'html' or 'text' must be provided.
The React version of the message. Only available in the Node.js SDK.
Custom headers to add to the email. Must be a dictionary/object with key-value pairs (e.g., {'X-Custom-Header': 'value'}). Pass None or omit to exclude.
Email subject.
Reply-to email address. For multiple addresses, send as an array of strings.
Schedule email to be sent later. The date should be in ISO 8601 format (e.g., '2024-08-05T11:52:01.858Z').
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_UPDATE_BROADCASTUpdate an existing broadcast in Resend. Use when you need to modify broadcast details like name, subject, content, or recipients.
Input parameters
The Broadcast ID to update.
The email address of the sender.
The HTML version of the message.
Name of the broadcast.
The plain text version of the message.
The subject line of the email.
The email addresses to which replies should be sent.
Unique identifier of the segment this broadcast will be sent to.
Unique identifier of the audience this broadcast will be sent to.
The preview text of the email.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_UPDATE_CONTACTTool to update an existing contact in Resend by ID or email. Use when you need to modify contact details such as name or subscription status.
Input parameters
The last name of the contact.
The first name of the contact.
The Contact ID or email address to update. Can be either the unique contact ID (UUID format) or the contact's email address.
The subscription status of the contact. When true, unsubscribes the contact from all broadcasts.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_UPDATE_CONTACT_PROPERTYUpdate an existing contact property in Resend. Only the fallback_value can be updated; the key and type fields cannot be changed after creation.
Input parameters
The default value to use when the property is not set for a contact. Must match the type specified in the contact property's type field. Can be a string or number.
The Contact Property ID to update.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_UPDATE_DOMAINUpdate an existing domain.
Input parameters
TLS setting for email communication. 'opportunistic': Always attempts to make a secure connection. 'enforced': Requires TLS for email communication.
The id of the domain to update.
Track the open rate of each email.
Track clicks within the body of each HTML email.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_UPDATE_EMAILUpdate a scheduled email.
Input parameters
The ID of the email to update.
Schedule email to be sent later. The date should be in ISO 8601 format (e.g: 2024-08-05T11:52:01.858Z).
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_UPDATE_TEMPLATETool to update an existing email template in Resend. Use when you need to modify template properties such as name, subject, HTML content, or variables.
Input parameters
The Template ID or alias to update.
Sender email address. To include a friendly name, use the format "Your Name <sender@domain.com>".
The HTML version of the template.
The name of the template.
The plain text version of the template.
The alias of the template.
Email subject.
Reply-to email addresses.
Template variables with their types and optional fallback values.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_UPDATE_TOPICTool to update an existing topic in Resend. Use when you need to modify the name of a topic.
Input parameters
The Topic ID to update.
The name of the topic to update.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_UPDATE_WEBHOOKTool to update an existing webhook configuration. Use when you need to modify the endpoint URL, change event subscriptions, or enable/disable a webhook.
Input parameters
Array of event types to subscribe to. Must contain at least one event if provided.
The status of the webhook. Set to 'enabled' to activate or 'disabled' to deactivate.
The URL where webhook events will be sent.
The ID of the webhook to update.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
RESEND_VERIFY_DOMAINVerify a domain through the Resend Email API. DNS records must fully propagate before verification succeeds; avoid immediate retries after DNS setup.
Input parameters
The id of the domain to verify. Must match an existing registered domain; use RESEND_LIST_DOMAINS to retrieve valid IDs.
Output
Data from the action execution
Error if any occurred during the execution of the action
Whether or not the action execution was successful or not
No publicly available marketplace agent is found using this tool yet. There are 55 agents privately built on Nagent that already use Resend.
Build on Nagent
Connect Resend to any Nagent agent in minutes — no API key management, no boilerplate. Just configure and deploy.
The five questions agent builders ask before adopting a new integration.
Open the External Integrations panel inside Nagent (app.nagent.ai/externalIntegration), find Resend, and click "Connect Now." You'll authenticate with an API key — Nagent handles credential storage and refresh automatically. Once connected, Resend is available to any agent in your workspace.
No. Nagent provides no-code integration for every tool. Once Resend is connected, you configure its 62 actions directly in the agent builder UI — no API calls, no boilerplate, no schema management.
Helix — Nagent's agentic agent builder — lets you drop Resend steps into any workflow visually. Pick an action (e.g., one of those listed above), fill in the inputs (Helix knows the required vs. optional schema for each parameter), and connect it to upstream/downstream steps. Triggers run as the entry point of an agent, so when a Resend event fires, the agent kicks off automatically.
Every Resend action and trigger ships with a fully-typed schema — input parameters with name, type, required flag, and description, plus the output payload shape. The schemas are documented in the sections above. Helix uses these schemas to validate your configuration at build time and to type-check the data flowing between steps.
Yes. While Resend ships with 62 pre-built email actions, you can layer custom logic around them inside Helix — pre/post-processing steps, conditional branches, retries, or stitching Resend together with other connected tools. For deeper customization, talk to our team about Nagent's Agentic AI Lab — forward-deployed engineers who build Resend-based workflows tailored to your business.