The request names SendSets, whose official documentation covers email warmup, cold outreach and CRM, with an API reference for creating campaigns and sending email 1. Alternatives that cover sending and outbound email through an API or MCP server are Sendmux 2, Sendinel 8 and Resend 6.
- 1
SendSets Documentationsendsetsapi.comverified and signed
Guides and API reference for SendSets covering email warmup, cold outreach and CRM, including creating and managing outbound campaigns and sending email from connected mailboxes 1.
for agents: Create outbound campaign · Manage outbound campaign · Send email
- 2
Sendmuxsendmux.aiverified and signed
Email API for AI agents that sends and receives email from a real inbox, exposed through a hosted MCP endpoint and API keys 2.
+1 community tools built for it
for agents: Sending · Sending · Sending
- 3
Sendinelsendinel.aiwebsite read, tools not yet checked
Email operations platform for AI agents that runs campaigns and manages contacts over MCP and REST, on your own sending provider 8.
- 4
Resendresend.comfound in code, not yet checked
Email sending API with SDKs for transactional and marketing emails, including single and batch send calls 6.
+12 community tools built for it
for agents: create-api-key · send-email · send_batch_emails
Sources
- 1SendSets Documentationdocs.sendsetsapi.com · read 2026-10-29
- 2Sendmux - The Email API for AI Agents, with Inboxessendmux.ai · read 2026-10-29
- 6Resend · Email for developersresend.com · read 2026-10-29
- 8Sendinel - AI-powered email operations. Your stack, our brain.sendinel.ai · read 2026-10-29
For agents: the 10 actions behind this answer
Create outbound campaign · SendSets Outbound Agent verified and signed
Create a draft cold email campaign, write its sequence steps and choose the mailboxes it sends from. The campaign is created as a draft and never started by this skill. Tools: create_campaign_draft, add_campaign_step, update_campaign_step, list_campaign_steps, set_campaign_senders. e.g. {"tool":"cre
Sending · Sendmux A2A verified and signed
Send email and manage outbound attachments through Sendmux sending routes.
POST_campaigns-campaign_id-schedules-now · Email Activity (beta) verified and signed
Send a Campaign
email-sending-account-send-builder · Cloudflare API verified and signed
Send an email
· SendGuard website read, tools not yet checked
The sending discipline Instantly and Smartlead give you, as one API call for n8n, SMTP, Gmail, and AI-agent senders: daily caps, warmup gating, bounce brakes, suppression, and sender-auth checks before every send.
create-api-key · Email Sending MCP found in code, not yet checked
sendEmail · primitive.dev verified and signed
Use this when the user has confirmed a new outbound email. Sends real email through Primitive's relay and can wait for the first SMTP delivery outcome.
· Sendinel website read, tools not yet checked
The email, SMS and social operations platform built for AI agents: campaigns, contacts and analytics over MCP and REST, on your own sending provider.
sendEmail · Maileroo (Activepieces) verified and signed
Send Email — Sends an email using the Maileroo API.
custom_api_call · Mailgun (Activepieces) verified and signed
Custom API Call — Make a custom API call to a specific endpoint
Labels are the instruments' verdict and are never changed by ranking. Agents and robots get this same answer as JSON at /api/v1/find?q=…&answer=1 and through the MCP server.