MJX CRM API rate limits, errors and CORS

Every MJX CRM API answer uses one JSON envelope, and every error carries a plain sentence you can show or log. This page lists the statuses, the limits and the CORS rules.

#The envelope

{ "success": true,  "data": { … } }
{ "success": false, "error": { "message": "That API key is not valid, or it was revoked." } }

Some site-wide errors (such as the general rate limit) add a code, for example "code": "RATE_LIMITED". Do not rely on the exact wording of messages — use the HTTP status in code, and show the message to people.

The MCP server uses JSON-RPC 2.0 errors instead; see MCP server.

#HTTP statuses

#Rate limits

The per-key limit counts by key, not by address, so several servers sharing one key share one budget. Answers carry the standard RateLimit-* headers so you can see how much is left. When you go over:

{ "success": false, "error": { "message": "Too many requests for this key — at most 120 a minute. Slow down and try again." } }

#Other limits

#CORS

#Retrying safely

• POST /leads — safe to retry: a known phone or email returns the existing lead.
• PATCH /leads/{id} — safe to retry: it sets values, it does not add to them.
• POST /leads/{id}/notes — not safe to retry blindly: each call adds a note.
• Webhooks to you — we retry once after a minute with the same X-MJX-Delivery; ignore a delivery id you have already handled.

#Versioning

The version is in the path (/api/v1/crm). New fields and endpoints can appear in v1 at any time; ignore fields you do not know. Removing or renaming a field would come with a new version path.

#Questions people ask