WeSend
mnen
Dashboard

API docs

Contacts

Add your customers to your WeSend contact list as they sign up, then send them promotions from the dashboard in one click.

A contact is someone you send promotions to: a phone number, an email address or both. Add them on the dashboard, from a CSV or Excel file, or with this API. Then, under Send, pick everyone, a group or a tag and send.

Promotions go out only between 09:00 and 21:00, Ulaanbaatar time. Every SMS starts with {brand}: and every email ends with an unsubscribe link, added automatically.

Add or update a contact

POST/v1/contacts

Adds a contact, or updates the one with the same external_id, phone or email.

Call it whenever someone registers in your system. Sending the same person again updates them instead of adding a second contact: they are matched by external_id, then phone, then email.

curl -X POST https://dev-api.wesend.mn/v1/contacts \
  -H "Authorization: Bearer $WESEND_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "external_id": "user_1024",
  "name": "Бат-Эрдэнэ",
  "phone": "99112233",
  "email": "[email protected]",
  "company": "DoDo Shop",
  "tags": [
    "vip"
  ],
  "groups": [
    "Шинэ хэрэглэгч"
  ],
  "marketing": {
    "sms": true,
    "email": true
  }
}'
Response201 Created
{
  "id": "0b9c1a52-6f0e-4d8b-9a3c-2f1e5d7c8a90",
  "external_id": "user_1024",
  "name": "Бат-Эрдэнэ",
  "phone": "99112233",
  "email": "[email protected]",
  "company": "DoDo Shop",
  "note": null,
  "tags": [
    "vip"
  ],
  "groups": [
    "Шинэ хэрэглэгч"
  ],
  "marketing": {
    "sms": "subscribed",
    "email": "subscribed"
  },
  "sandbox": false,
  "created_at": "2026-10-23T03:15:30.000Z",
  "updated_at": "2026-10-23T03:15:30.000Z",
  "created": true
}

Request fields

phonestring
An 8-digit Mongolian mobile number. phone or email is required.
emailstring
An email address.
external_idstring
The person's id in your system, up to 100 characters. Finds the same person even after their phone or email changes.
namestring
Full name, up to 120 characters.
companystring
Company.
notestring
An internal note, up to 1,000 characters.
tagsstring[]
Up to 20 tags. Replaces the contact's tags when sent.
groupsstring[]
Group names. A group that does not exist yet is created. Replaces the contact's groups when sent.
marketing.smsboolean
true: agreed to promotional SMS. false: said no.
marketing.emailboolean
true: agreed to promotional email. false: said no.
  • A new contact answers 201, an updated one 200; created says which.
  • Fields you leave out stay as they are. null clears a field.
  • A project keeps up to 100,000 contacts and 100 groups.
  • Contacts added with a sandbox key are kept apart, never shown on the dashboard or sent to, and deleted after 30 days.

Consent to promotions

Each contact has a marketing state per channel: unknown, subscribed or unsubscribed. An unknown contact receives promotions until they say no; an unsubscribed one never does.

  • A no sticks. Deleting a contact and adding it again, or an import, does not turn it back on.
  • When someone turns promotions off in your app, send marketing.sms: false with PATCH /contacts/{id}. SMS cannot be answered with STOP, so this is the main way an SMS opt-out reaches WeSend.
  • true lifts a no your project recorded. It does not lift one the person made themselves, with the unsubscribe link or by marking an email as spam.

Add many at once

POST/v1/contacts/bulk

Up to 1,000 contacts in one call. Each is answered on its own: one bad row does not stop the rest.

curl -X POST https://dev-api.wesend.mn/v1/contacts/bulk \
  -H "Authorization: Bearer $WESEND_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "contacts": [
    {
      "external_id": "user_1024",
      "phone": "99112233",
      "name": "Бат-Эрдэнэ"
    },
    {
      "external_id": "user_1025",
      "email": "[email protected]",
      "name": "Сараа",
      "marketing": {
        "email": true
      }
    }
  ]
}'
Response200 OK
{
  "created": 1,
  "updated": 1,
  "results": [
    {
      "id": "0b9c1a52-6f0e-4d8b-9a3c-2f1e5d7c8a90",
      "created": false
    },
    {
      "id": "7d3e2f10-1c4b-4a8e-9f62-3b5a7c9d0e21",
      "created": true
    }
  ]
}

Find and list

GET/v1/contacts

A page of contacts, or the one contact with an external_id, phone or email.

curl "https://dev-api.wesend.mn/v1/contacts?external_id=user_1024" \
  -H "Authorization: Bearer $WESEND_API_KEY"

Filters

external_id, phone, emailstring
Finds one contact.
qstring
Searches name, phone, email and company.
tagstring
Contacts with the tag.
groupstring
A group name.
page, limitnumber
The page, and 1 to 100 per page (50 by default).
GET/v1/contacts/{id}

One contact.

GET/v1/contact-groups

The project's groups.

Update and delete

PATCH/v1/contacts/{id}

Changes only the fields that are sent.

curl -X PATCH https://dev-api.wesend.mn/v1/contacts/0b9c1a52-6f0e-4d8b-9a3c-2f1e5d7c8a90 \
  -H "Authorization: Bearer $WESEND_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "marketing": {
    "sms": false
  }
}'
DELETE/v1/contacts/{id}

Deletes the contact. Any no it gave is kept.

curl -X DELETE https://dev-api.wesend.mn/v1/contacts/0b9c1a52-6f0e-4d8b-9a3c-2f1e5d7c8a90 \
  -H "Authorization: Bearer $WESEND_API_KEY"
Response200 OK
{
  "id": "0b9c1a52-6f0e-4d8b-9a3c-2f1e5d7c8a90",
  "deleted": true
}