Legacy API (v2)

The legacy v2 API lets existing integrations send and receive faxes, manage fax numbers, send secure email links, create clients, and run AI on documents.

These examples use /api/v2 and developer-owned fax resources. For organization-linked web fax workflows, use the main Sent Faxes and Received Faxes documentation. Changing the API URL alone does not enroll an account or migrate its history.

Quickstart: Send your first fax

Use a test key (sk_test_…) and a small PDF. This posts to the fax API and returns a token to check status.

export API_BASE="https://api.medsender.com/api/v2"
export API_KEY="sk_test_..."

# Provision a test fax number (area code 415 as example)
curl -s -X POST -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"fax_number":{"area_code":"415"}}' \
  "$API_BASE/fax_numbers" | jq

# Send a fax (replace numbers and attach sample.pdf)
curl -s -X POST -H "Authorization: Bearer $API_KEY" \
  -F "file=@./sample.pdf" \
  -F "from_number=+14155550100" \
  -F "to_number=+13125550123" \
  "$API_BASE/sent_faxes"

bash

export API_BASE="https://api.medsender.com/api/v2"
export API_KEY="sk_test_..."

# Provision a test fax number (area code 415 as example)
curl -s -X POST -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"fax_number":{"area_code":"415"}}' \
  "$API_BASE/fax_numbers" | jq

# Send a fax (replace numbers and attach sample.pdf)
curl -s -X POST -H "Authorization: Bearer $API_KEY" \
  -F "file=@./sample.pdf" \
  -F "from_number=+14155550100" \
  -F "to_number=+13125550123" \
  "$API_BASE/sent_faxes"

export API_BASE="https://api.medsender.com/api/v2"
export API_KEY="sk_test_..."

# Provision a test fax number (area code 415 as example)
curl -s -X POST -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"fax_number":{"area_code":"415"}}' \
  "$API_BASE/fax_numbers" | jq

# Send a fax (replace numbers and attach sample.pdf)
curl -s -X POST -H "Authorization: Bearer $API_KEY" \
  -F "file=@./sample.pdf" \
  -F "from_number=+14155550100" \
  -F "to_number=+13125550123" \
  "$API_BASE/sent_faxes"

Endpoints (Customer)

Sent Faxes: GET /sent_faxes, GET /sent_faxes/:send_token, POST /sent_faxes
Received Faxes: GET /received_faxes, GET /received_faxes/:send_token, POST /received_faxes/test_receive, POST /received_faxes/:send_token/forward_as_fax
Fax Numbers: GET /fax_numbers, GET /fax_numbers/:slug, POST /fax_numbers, PATCH /fax_numbers/:slug
Clients: GET /clients, GET /clients/:client_id, POST /clients, PATCH /clients/:client_id
Secure Links: POST /emails, GET /emails/:email_id
AI Documents: GET /ai_documents, GET /ai_documents/:ai_token, POST /ai_documents

All calls use Authorization: Bearer sk_* with your API key. Test keys start with sk_test_.

Response Examples

Create (Send Fax)

{ "message": "Record has been sent, we will send a callback upon completion.", "faxId": "abc123" }

JSON

{ "message": "Record has been sent, we will send a callback upon completion.", "faxId": "abc123" }

{ "message": "Record has been sent, we will send a callback upon completion.", "faxId": "abc123" }

List (Fax Numbers)

{
  "faxNumbers": [{
    "id": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
    "number": "+15550100001",
    "callbackUrl": null,
    "createdAt": "2025-01-15T10:30:00.000Z",
    "client": null,
    "uri": "https://api.medsender.com/api/v2/fax_numbers/f47ac10b-58cc-4372-a567-0e02b2c3d479"
  }]
}

JSON

{
  "faxNumbers": [{
    "id": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
    "number": "+15550100001",
    "callbackUrl": null,
    "createdAt": "2025-01-15T10:30:00.000Z",
    "client": null,
    "uri": "https://api.medsender.com/api/v2/fax_numbers/f47ac10b-58cc-4372-a567-0e02b2c3d479"
  }]
}

{
  "faxNumbers": [{
    "id": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
    "number": "+15550100001",
    "callbackUrl": null,
    "createdAt": "2025-01-15T10:30:00.000Z",
    "client": null,
    "uri": "https://api.medsender.com/api/v2/fax_numbers/f47ac10b-58cc-4372-a567-0e02b2c3d479"
  }]
}