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Overview Send single, transactional messages with the v1 API using your active identity. Steps
  1. Create an API key
  • In Settings → API → Create API key.
  • Restrict scopes to send_email if needed; set a per-minute rate cap if desired.
  1. Call the API (idempotent)
BASE=https://api.fluxomail.com
curl -X POST "$BASE/api/v1/emails/send" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $API_KEY" \
  -H "Idempotency-Key: send-$(uuidgen)" \
  -d '{
    "to": "user@example.com",
    "subject": "Welcome",
    "content": "Hi",
    "htmlContent": "<p>Hi</p>"
  }'
  1. Handle responses
  • Success: { sendId, status: "sent", messageId } (reused on duplicate keys)
  • 401/403: invalid key or missing scope
  • 429: retry after Retry-After seconds with same Idempotency-Key
  1. View delivery timeline
  • Use GET /api/v1/sends/{id} for messages + events (sent, delivered, opened, clicked).
Notes
  • From identity is auto-selected from your organization’s active configuration.
  • Open/click tracking is injected automatically into HTML.
Related
  • API: Send email (v1)
  • API: Get send timeline
  • API: Idempotency, Rate limits
Error resolution matrix
ErrorSymptomLikely causeResolution
400Missing required fieldsto, subject, or content omittedProvide all required fields
401Invalid API keyOmitted/incorrect Authorization/x-api-keyCreate a new key or correct header
403Missing scope send_emailKey lacks send_email scopeGrant scope or use a key without scopes
403Tenant pausedOrganization is pausedResume in Settings → Deliverability
429Rate limit exceededPer-minute cap hitWait Retry-After seconds and retry with same Idempotency-Key
500Provider/internal errorTransient failureRetry with same Idempotency-Key; contact support with sendId
Email support@fluxomail.com with your sendId and timestamp.