One Agent Identity Per Customer: Multi-Tenant Email

Provisioning a tenant-scoped email identity for your SaaS is one POST: curl --request POST \ --url "https://api.us.nylas.com/v3/connect/custom" \ --header "Authorization: Bearer <NYLAS_API_KEY>" \ --header "Content-Type: application/json" \ --data '{ "provider": "nylas", "workspace_id": "<WORKSPACE_ID>", "settings": { "email": "scheduling@customer-a.com" } }' No OAuth dance, no refresh token — just an address on a registered domain. The response comes back already valid: { "request_id" : "5967ca40-a2d8-4ee0-a0e0-6f18ace39a90" , "data" : { "id" : "b1c2d3e4-5678-4abc-9def-0123456789ab" , "provider" : "nylas" , "grant_status" : "valid" , "email" : "scheduling@customer-a.com" , "scope" : [], "created_at" : 1742932766 } } The data.id is a grant_id that works with every existing Nylas endpoint, and the account is live immediately. That's the primitive behind a multi-tenant pattern worth knowing: one Agent Account per customer, on each customer's own verified domain, all managed from a single application. (Agent Accounts are in beta, so the surface may shift before GA.) The architecture in one paragraph Your app runs scheduling@customer-a.com , scheduling@customer-b.com , and so on — same code path, different identities. Each account has its own policy, its own send quota, and its own sender reputation. A single application can manage accounts across an unlimited number of registered domains, so tenant count is a billing question, not an architectural one. Customer A's deliverability problems stay Customer A's; nothing they do contaminates Customer B's mail. Domains: register once, mint accounts forever The provisioning docs lay out two domain strategies you can mix freely in one application: Strategy Address format Setup Trial domain alias@<your-application>.nylas.email None — instant Your own domain alias@yourdomain.com MX + TXT records at the DNS provider For the per-customer pattern, each tenant brings their domain. You register it once per organization (picking the US