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Documentation Index

Fetch the complete documentation index at: https://orbit-docs.devotel.io/llms.txt

Use this file to discover all available pages before exploring further.

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Fax

Orbit’s Fax channel sends and receives T.38 / G.711 faxes via tier-1 carriers (Telnyx, DIDWW). Documents are delivered as PDF or TIFF; status updates flow through the same webhook contract as other channels. Fax is on-success-charge: Orbit only bills your wallet when the carrier confirms a successful fax transmission. Failed attempts (busy, no-answer, line-quality) are NOT billed.

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Send a fax

curl -X POST https://orbit-api.devotel.io/api/v1/messages/fax \
  -H "X-API-Key: dv_live_sk_..." \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+14155552671",
    "from": "+18005551234",
    "media_url": "https://example.com/contract.pdf",
    "options": {
      "quality": "high",
      "header_text": "Acme Corp — Contract"
    }
  }'

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Response

{
  "data": {
    "fax_id": "fax_abc123",
    "status": "queued",
    "channel": "fax"
  },
  "meta": {
    "request_id": "req_xyz789",
    "timestamp": "2026-05-09T00:00:00Z"
  }
}

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Capabilities

  • Outbound fax — PDF or TIFF input; carrier converts to T.38 packets in real time.
  • Inbound fax — incoming faxes are stored as PDF in Orbit’s secure storage, with the page count, sender ANI, and a download URL POSTed to your webhook.
  • Quality + header — standard (98 dpi) or high (196 dpi); custom header text injected on every page.
  • Multi-page — up to 200 pages per outbound fax; carrier-imposed cap.
  • Status + page count — fax.delivered / fax.failed events include pages_sent, total_pages, and the carrier-side fax-call ID for reconciliation.
  • Per-tenant carrier connection — orgs can attach a dedicated Telnyx Fax application or DIDWW account for compliance / data-residency.

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Status flow

queued → sending → delivered (or failed) Failure reasons surface in the failure_reason field: BUSY, NO_ANSWER, NO_FAX_TONE, BAD_LINE_QUALITY, RECIPIENT_REJECTED.

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Common errors

CodeHTTPCauseFix
FAX_INVALID_NUMBER422to is not a valid E.164 phone number.Verify the format +<country><area><number>.
FAX_MEDIA_FETCH_FAILED422Orbit could not download media_url (timeout, 404, or non-public).Make the URL publicly fetchable, or upload to /v1/files and pass the resulting Orbit file URL.
FAX_UNSUPPORTED_FORMAT415The fetched media is not PDF or TIFF.Convert to PDF or TIFF before sending; PNG / JPG is not accepted natively.
FAX_TOO_MANY_PAGES422Document exceeds 200 pages.Split into multiple faxes.
FAX_RECIPIENT_REJECTED(status=failed)Recipient hung up before the handshake completed.Retry once with quality=standard to reduce the negotiation time, or contact the recipient.

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Pricing

Per-page on success only. International rates vary by destination. See the pricing page.