Wassenger contacts

Wassenger Contacts

The audience side of WhatsApp: who you can reach, what you know about them, and the opt-in trail behind each one. Scoped to WABA — for the WABA-vs-QR rationale see wassenger-setup.

The Wassenger MCP has no general contacts tool. There is no get_contacts, search_contacts, get_contact_details, or export_contacts. Standalone contact CRUD, search, segmentation, import, and export are done against the REST /contacts API (direct HTTPS calls with a Token: <API_KEY> header — clearly labelled REST throughout the recipes below). The MCP only touches contact data three indirect ways: search_whatsapp_chats_by_name (find a chat and its embedded chat.contact), manage_whatsapp_campaign_contacts (recipients inside a campaign), and verifyWhatsAppNumberExists (is this number on WhatsApp).

When to use

• "Import this CSV of contacts into Wassenger."
• "Sync my HubSpot contacts to Wassenger so I can message them via the campaign module."
• "Find every customer in Spain tagged 'vip'."
• "Export every contact we haven't messaged in 90 days."
• "Check whether +44 7700 900111 is on WhatsApp before I send."

For sending messages to these contacts, route to wassenger-messaging. For bulk outbound, wassenger-campaigns. For organizing the chats that come back, wassenger-inbox.

Prerequisites

• wassenger-setup complete.
• A device with status: ready (WABA).
• For CSV import: a column with phone numbers in E.164 (+34600111222).
• For CRM sync: API access to the CRM and a strategy for opt-in evidence (see wassenger-marketing for the compliance baseline).

Recipes

Recipe 1 — Import from CSV

"I have a spreadsheet of customers from my point-of-sale. Import them."

CSV format (UTF-8, comma-separated):
  phone,first_name,last_name,email,labels,language,opt_in_at,opt_in_source
  +34600111222,Marta,Lopez,[email protected],vip;es,es,2026-04-10,checkout_form
  +34611222333,Juan,Pérez,[email protected],es,es,2026-04-10,checkout_form

Flow:

1. upload_whatsapp_file_from_url with the CSV URL  → file.id   (MCP tool)
2. Direct REST call — Token: <API_KEY> header:
   POST https://api.wassenger.com/v1/contacts/import
     body: { file: <file.id>, device: <id> }
   (Async — returns an import job id.)
3. Poll (REST): GET https://api.wassenger.com/v1/contacts/import/{jobId} until status=done.

Custom columns survive as fields you can later use as template variables ({{first_name}}).

Always import an opt-in trail (opt_in_at, opt_in_source). Without it you cannot defensibly send Marketing templates and Meta will eventually catch up.

Recipe 2 — Sync from a CRM

For each contact in the CRM:

1. verifyWhatsAppNumberExists with phoneNumber: <phone>   (MCP tool)
   → if false, skip (don't waste a Wassenger contact slot)
2. Look up the contact by phone — direct REST call, Token: <API_KEY> header:
   GET https://api.wassenger.com/v1/contacts?phone=<phone>
   - if found: PATCH https://api.wassenger.com/v1/contacts/{id} with updated metadata
   - else:     POST https://api.wassenger.com/v1/contacts with phone + name + custom fields
3. (Optional) tag the resulting chat with the CRM segment via the MCP send action:
   search_whatsapp_chats_by_name(<phone>) → chat.wid, then
   send_whatsapp_message action: agent, chat: <chat.wid>, agentId: <id>,
     actions: [ { action: "labels:add", params: { labels: ["<crm-segment-label>"] } } ]

Batch in chunks of ~50 to avoid rate limits. Idempotency: always search by phone first; never blindly POST.

Common CRM patterns:

CRM	Recommended bridge
HubSpot	Workflow → Webhook to your function, or use n8n-wassenger
Pipedrive	App webhooks on contact create/update
Salesforce	Outbound Message → middleware → Wassenger REST
Attio	Webhook automations
Custom (Postgres / Notion / Airtable)	Scheduled job (cron / Inngest) that reads delta and patches

Recipe 3 — Segment & export

There is no contacts MCP tool — segment with the REST /contacts list endpoint (direct call, Token: <API_KEY> header), passing filters as query params:

# Direct REST call — Token: <API_KEY> header
GET https://api.wassenger.com/v1/contacts?labels=vip&country=ES&lastInboundAfter=2026-04-01
  → results (paginated)

Export to CSV for back-office use (also REST — the list endpoint supports a CSV format):

# Direct REST call — Token: <API_KEY> header
GET https://api.wassenger.com/v1/contacts?labels=vip&country=ES&format=csv
  → CSV payload (stream/save it yourself)

Useful for mailing lists outside WhatsApp, CRM cleanup, BI dashboards, GDPR data-export requests.

Recipe 4 — Search

Two ways, depending on what you have:

# A) Find a chat (and its embedded chat.contact) by name — MCP tool:
search_whatsapp_chats_by_name with query: "marta"

# B) Search the contact directory itself — direct REST call, Token: <API_KEY> header:
GET https://api.wassenger.com/v1/contacts?search=marta   → name OR phone matches

For an exact phone lookup, prefer the phone= filter on the REST endpoint (GET …/v1/contacts?phone=<phone>) — faster than a text search and returns the canonical record.

Recipe 5 — Validate a phone before sending

The cheapest sanity check before any outbound message to a new contact:

verifyWhatsAppNumberExists
  - phoneNumber: "+34600111222"   # E.164. This tool takes ONLY phoneNumber — no device.
  → whether the number is on WhatsApp (+ the canonical international format)

Run this before the first message to:

• Skip non-WhatsApp numbers (don't burn a template quota on a useless send).
• Catch typos (Meta returns the canonical international format on success).
• Avoid WABA template-failure penalties (sending to non-existent numbers triggers Meta's quality-rating system).

Recipe 6 — Per-contact attributes for personalization

Wassenger stores arbitrary custom fields on contacts. Use them as template variables:

# Direct REST call — Token: <API_KEY> header
PATCH https://api.wassenger.com/v1/contacts/{id}  body: {
  customFields: {
    plan_tier: "premium",
    lifetime_value: 1240,
    last_purchase: "2026-04-15"
  }
}

Then in a campaign template:

"Hi {{first_name}}, your {{plan_tier}} plan renews on {{renewal_date}}."

Keep custom fields small and meaningful — every contact carries them, so excessive metadata bloats the contact record and slows pagination.

Anti-patterns

• Mass-importing scraped or purchased phone lists. Fastest way to a WABA suspension. Build opt-in from day one.
• No opt-in trail. If you can't show when and where each contact opted in, you cannot defensibly run Marketing campaigns. Capture it at the source (form, checkout, store).
• Verifying every contact on every send. verifyWhatsAppNumberExists is for first contact. After that, trust your DB until you see a failure.
• Mixing phone formats. Always store E.164 (+34600111222). Mixed formats (0034600111222, 600111222, +34 600 111 222) cause silent lookup misses.
• Custom fields as a junk drawer. If a field is only used by one campaign once, don't persist it as a contact attribute — keep it on the campaign side.
• Forgetting to mirror opt-out. When a contact opts out (via STOP keyword — see wassenger-marketing), update the contact's optedOut field everywhere, not just on Wassenger.

See also

• wassenger-messaging — sending to these contacts.
• wassenger-campaigns — bulk outreach to segments.
• wassenger-inbox — once contacts message you, manage the resulting chats.
• wassenger-marketing — opt-in / opt-out compliance baseline.
• wassenger-mcp — exact tool parameter shapes (references/tools-reference.md).