POST https://api.render.com/v1/services/{serviceId}/custom-domains with body {"name": "<domain>"} — 201 = added; verification is kicked off automatically (https://api-docs.render.com/reference/create-custom-domain).
Point the domain's DNS at the service, then re-check verification any time with POST https://api.render.com/v1/services/{serviceId}/custom-domains/{customDomainNameOrId}/verify — accepts the domain name OR its id; 202 = verification triggered (https://api-docs.render.com/reference/refresh-custom-domain).
List/inspect domains: GET /v1/services/{serviceId}/custom-domains (https://api-docs.render.com/reference/list-custom-domains).
Known gotchas
402 (payment required) and 409 (conflict, e.g. domain already in use) are documented error responses on create (https://api-docs.render.com/reference/create-custom-domain).
The verify endpoint returns 202 (async trigger), not a synchronous verified/unverified answer — poll the domain resource for status (https://api-docs.render.com/reference/refresh-custom-domain).
Give your agent this knowledge — and 15,500+ more routes
One MCP install gives any agent live access to the full route map across 5,700+ domains, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp
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