How to check a number in Python with the Wapito WhatsApp API

Before you start

• pip install requests
• os.environ["WAPITO_TOKEN"]
• A channel with a WhatsApp number linked to it, and its API token. Create one in the dashboard — the authentication guide shows where the token goes.

The whole script

Every step above in one runnable file. Save it as check-number.py, put your token in the environment, and run it.

"""Check Number with the Wapito WhatsApp API.

Normalise to international format, check in modest batches, and store every result with its date so you never check the same number twice.

Run it with:
    export WAPITO_TOKEN="wpt_..."
    python check-number.py
"""
import os

import requests

BASE_URL = "https://api.wapito.com/v1"
TOKEN = os.environ["WAPITO_TOKEN"]

# --- Normalise the numbers first ---
url = BASE_URL + "/contacts/+15551234567/exists"

headers = {"Authorization": "Bearer " + TOKEN}

response = requests.get(url, headers=headers)

print(response.json())

# --- Check a batch ---
url = BASE_URL + "/contacts/check"

payload = { "phones": ["+15551234567", "+15559876543", "+15550000000"] }
headers = {
    "Authorization": "Bearer " + TOKEN,
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())

# --- Store the result and watch the allowance ---
url = BASE_URL + "/usage"

querystring = {"from":"2026-09-01","to":"2026-09-15"}

headers = {"Authorization": "Bearer " + TOKEN}

response = requests.get(url, headers=headers, params=querystring)

print(response.json())

Receive the webhook

FastAPI receiver for channel — it verifies the signature, answers immediately and does the work after. Install it with pip install fastapi uvicorn and save it as webhook.py.

import hashlib
import hmac
import os
import time

from fastapi import FastAPI, Header, HTTPException, Request

app = FastAPI()
SECRET = os.environ["WAPITO_WEBHOOK_SECRET"].encode()
EVENTS = ["channel"]


def verify(raw: bytes, header: str | None) -> bool:
    """Checks the X-Wapito-Signature header: t=<ms>,v1=<hex hmac-sha256>."""
    if not header:
        return False
    parts = dict(p.split("=", 1) for p in header.split(",") if "=" in p)
    ts, sig = parts.get("t"), parts.get("v1")
    if not ts or not sig:
        return False
    if abs(time.time() * 1000 - int(ts)) > 300_000:  # 5 minute clock skew
        return False
    expected = hmac.new(SECRET, ts.encode() + b"." + raw, hashlib.sha256).hexdigest()
    return hmac.compare_digest(expected, sig)


@app.post("/wapito")
async def wapito(request: Request, signature: str | None = Header(default=None, alias="X-Wapito-Signature")):
    raw = await request.body()
    if not verify(raw, signature):
        raise HTTPException(status_code=401, detail="bad signature")
    payload = await request.json()
    if payload["event"] in EVENTS:
        print(payload["event"], payload["data"])
    return {"ok": True}  # answer 2xx fast; do the real work in a queue

Errors you may hit

• plan_required (402)
• not_on_whatsapp (404)
• quota_exceeded (429)

Gotchas

• requests does not raise on a 4xx by itself. Call response.raise_for_status() or check response.ok, otherwise a 429 send_rate_limited silently looks like a successful send and your loop keeps hammering the queue.
• json= and data= are not interchangeable. Pass json={...} so requests sets Content-Type: application/json and encodes UTF-8 for you; data= with a dict sends form encoding and the API answers 400 invalid_request.
• The default requests timeout is None, which means a stalled connection hangs your worker forever. Always pass timeout=(5, 30) and treat a read timeout as "maybe delivered" - re-check with the message id before you send again.
• A group id such as 120363000000000000@g.us is a string, not a number. Building it with an f-string from an int drops the precision and you get 404 not_found.
• Emoji and accented text need no extra work in Python 3, but reading a CSV of numbers with the default encoding on Windows will mangle them - open files with encoding="utf-8".

Where to run it

• Google Cloud Run (container, scale to zero, one revision per deploy)
• Render background worker for the sender, Render web service for the webhook receiver
• A 1 GB VPS with systemd for the worker and Caddy in front of the FastAPI receiver
• AWS Lambda + API Gateway for the webhook receiver only (the sender needs a long-lived process for queue spacing)

Pitfalls in Python

• phonenumbers.parse without a default region raises NumberParseException on a local number; pass the country you expect and catch the exception per row so one bad line does not end the run, collecting the failures with their line numbers for a manual pass afterwards. is_valid_number is a separate call and worth making before the format, since parse accepts digit strings that no carrier has ever issued.
• A pandas merge on a column of numbers that were read as int64 has lost leading plus signs and sometimes digits; read the number column as str with dtype and keep it that way through every transform, including the write back to CSV, which will otherwise reformat it.
• Wrapping the batch call in a retry decorator that retries on any HTTPError re-sends a batch that was answered 429 for quota, which burns the reset window; retry only on network errors, and make the decorator re-raise the 429 so the caller can end the run cleanly. tenacity's retry_if_exception_type with requests.ConnectionError expresses exactly that rule.

Frequently asked questions

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