DEVELOPER DOCUMENTATION

From request to delivery.

Register and confirm your email, generate an API key, then send sandbox messages to your confirmed address. Verify your domain to unlock production sending.

Send an email

curl https://mail.xdigitex.com/v1/emails \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Idempotency-Key: your-event-reference" \
  -H "Content-Type: application/json" \
  -d '{"from":"onboarding@xdigitex.com",
       "to":"your-confirmed-address@example.com",
       "subject":"Your integration works",
       "html":"<h1>Hello from your application</h1>",
       "text":"Hello from your application"}'

Response: HTTP 202 with an email ID and status queued. Reusing an idempotency key returns the existing email. Limits count recipients, not API calls.

Endpoints

Endpoint	Purpose
POST /v1/emails	Queue mail; optional template_id and variables
GET /v1/emails, /v1/emails/{id}	Tenant delivery history
GET/POST /v1/domains	Add domain and retrieve required DNS records
POST /v1/domains/{id}/verify	Queue automatic DNS checks
GET/POST /v1/templates	Saved designs with {{variable}} placeholders
POST /v1/templates/preview	Render safe branded HTML
GET/POST /v1/webhooks	Configure signed delivery callbacks
GET /v1/events	Delivery events for your account

SMTP

Host: mail.xdigitex.com · Port: 2465 · Implicit TLS required.
Username: apikey · Password: an active API key.
The same domain, recipient and quota rules apply. HTML/text messages are supported; attachments are not supported in this release.

Signed webhooks

Verify HMAC-SHA256 with your webhook secret against timestamp + "." + raw_request_body. Headers: X-Xdigitex-Timestamp, X-Xdigitex-Signature, X-Xdigitex-Event-Id. Reject timestamps older than five minutes and deduplicate event IDs. Webhooks retry with backoff. Only public HTTPS destinations on port 443 are supported.

Delivery states

Queued → accepted by our SMTP server → delivered to the recipient server. Deferred deliveries remain in Postfix's delivery queue. Permanent bounces suppress the recipient. Uncertain submissions are held for review to prevent blind duplicates. Recipient-server acceptance does not prove inbox placement.

Recipient quotas and notifications

Free: 4,000/month, 100/rolling hour. Starter: $3, 15,000/month, 500/hour. Growth: $5, 30,000/month, 750/hour. Business: $7, 70,000/month, 3,000/hour. Monthly quotas reset on the first UTC calendar day. Accepted recipient reservations count once; retries and repeated idempotency keys do not add usage. Failed deliveries remain counted.

HTTP quota rejections return 429 with Retry-After. SMTP returns temporary 451. Hourly cooldowns are 10–60 minutes; active retries and monthly exhaustion do not add strikes. Seven compliant days reset strikes. Essential security, authentication and billing mail is system-funded. Eligible service notices can count against customer monthly usage. GET /v1/notifications exposes category, quota impact and delivery state.