Valid leads can go straight to your Smartlead or Instantly campaign.See integrations
Start free
REST API, v1

Verify catch-all emails
from your own code

A small REST API with the same engine as the dashboard. Send addresses, carry on with your work, and get a signed callback when each verdict lands.

Read the API referenceGet an API key

Submit an address

Authenticate with the x-api-key header. Keys belong to one workspace and spend that account’s credits: 1 per well-formed address. Malformed addresses come back invalid straight away, free.

Most addresses start as pending and resolve within 24–48 hours. Add a callback_url so you don’t have to poll.

POST /v1/verify
curl https://api.bouncebrake.com/v1/verify \
  -H "x-api-key: $BOUNCEBRAKE_KEY" \
  -H "content-type: application/json" \
  -d '{"email":"maria.alvarez@harborline.co","callback_url":"https://your-app.example/bb","identifier":"crm-48121"}'

# 200
{"id": 90211, "email": "maria.alvarez@harborline.co",
 "status": "pending", "identifier": "crm-48121"}

Check the signature

Each callback carries X-BounceBrake-Signature: sha256=<hex>, an HMAC-SHA256 of the raw body. The signing key is the hex SHA-256 of your API key, so there’s no extra secret to store. Failed deliveries are retried with backoff, up to 5 attempts over about four hours.

verify_signature.py
import hashlib, hmac

def verified(raw_body: bytes, header: str, api_key: str) -> bool:
    key = hashlib.sha256(api_key.encode()).hexdigest().encode()
    want = "sha256=" + hmac.new(key, raw_body, hashlib.sha256).hexdigest()
    return hmac.compare_digest(want, header)

Endpoints

MethodPathDoes
POST/v1/verifyVerify one address
POST/v1/verify/bulkVerify up to 100 addresses in one call
GET/v1/verify/{id}Status of one submitted address
GET/v1/verify?email=Latest result for an address in this workspace
POST/v1/filesUpload a CSV (up to 50 MB) and start it
GET/v1/files/{id}Progress and counts for a file
GET/v1/files/{id}/downloadSigned link to the all, valid or invalid CSV
GET/v1/creditsYour account’s credit balance

10 requests per second per key. Full request and response shapes, errors and limits are in the API reference.

Free to start

Get a key and send your first address.

Start with 100 free credits. Upload your catch-all segment and see the verdicts for yourself.

Start free with 100 creditsSee pricing
  • No card needed
  • Duplicates are free
  • No verdict, credit back