Sendly email API and SDK documentation
Sendly docs: send transactional email by API or SDK, run campaigns and automation workflows, set up a sending domain, and migrate from Resend or SendGrid.
What is Sendly?
Sendly is an email platform for developers, built on top of AWS SES. It handles transactional sends, marketing campaigns, and automation workflows against the same contact database, and is designed to scale to millions of contacts.
Key Features
Drop-in Provider Compatibility
Already on Resend, SendGrid, Postmark, Mailgun, or Plunk? Keep your existing vendor SDK — swap the base URL and API key
Transactional Emails
Send transactional emails via API with template support and variable substitution
Email Campaigns
Create and send one-time email broadcasts to your contacts with advanced scheduling
Marketing Automation
Build automated email sequences with visual workflow builder and conditional logic
Contact Management
Manage millions of contacts with custom fields and CSV import capabilities
Dynamic Segmentation
Create dynamic audience segments based on contact data and behavior
Email Templates
Create reusable email templates for transactional and marketing emails
Event Tracking
Track events and use them to trigger workflows and segment audiences
Billing
Understand Sendly's billing model and pricing
MCP for AI Agents
Connect Claude or any MCP client so an agent can work in your Sendly account, with the permissions you choose
Onboard your agent
One prompt an AI coding agent can fetch and run to connect itself to Sendly — Claude Code, Codex, Cursor, and more
Quick Links
API Reference
Explore the complete API documentation
Self-Hosting
Deploy Sendly on your own infrastructure
Domain Verification
Learn how to verify your domains for sending emails
Guided DNS Setup
Let Sendly publish your DNS records for you and watch them for drift
API Keys
Manage your API keys and authentication
Glossary
Plain definitions of the email terms that show up in the dashboard, in an API error, or in a conversation about why a message did not arrive
FAQ
Answers to the questions Sendly actually gets, about agents, pricing and SDKs
Open Source
The official Sendly SDKs are open source on GitHub — sendly-js and sendly-python. Issues and contributions are welcome.
Support
If you need help or have questions:
- Read the documentation
- Open an issue on the SDK repositories
- Email support@sendly.now
- Join the Sendly Discord to ask the team and other developers