Marketstack email verification with BillionVerify
Marketstack is a real-time and historical stock market data API used by developers and fintech applications to power financial analytics. When your platform collects user emails for alerts, reports, or account access, BillionVerify ensures those addresses are deliverable so your market data notifications actually reach recipients.
Why verify before the send
Financial alert services live and die by email reliability. A user who signs up with a disposable address will never receive price alerts or report digests, creating a silent churn problem. BillionVerify validates emails at the point of capture, filtering out throwaway inboxes and unroutable addresses before they enter your user base.
Ready-to-use n8n workflow
Import this workflow into n8n — it verifies every address with BillionVerify before Marketstack sends, so only deliverable contacts are emailed. Install the BillionVerify community node first, then add your API key.
{
"name": "Verify emails before sending in Marketstack + BillionVerify",
"nodes": [
{
"parameters": {},
"type": "n8n-nodes-base.manualTrigger",
"typeVersion": 1,
"position": [
240,
300
],
"name": "When clicking ‘Test workflow’"
},
{
"parameters": {
"assignments": {
"assignments": [
{
"id": "email-field",
"name": "email",
"value": "jane@example.com",
"type": "string"
}
]
},
"options": {}
},
"type": "n8n-nodes-base.set",
"typeVersion": 3.4,
"position": [
460,
300
],
"name": "Get contacts"
},
{
"parameters": {
"sendTo": "={{ $json.email }}",
"subject": "Message for Marketstack contacts",
"message": "Replace this Gmail send with your Marketstack node — only deliverable, verified contacts reach it.",
"options": {}
},
"type": "n8n-nodes-base.gmail",
"typeVersion": 2.1,
"position": [
900,
300
],
"name": "Send email",
"webhookId": "",
"credentials": {
"gmailOAuth2": {
"id": "",
"name": "Gmail account"
}
}
},
{
"parameters": {
"operation": "verify",
"email": "={{ $json.email }}",
"additionalOptions": {}
},
"type": "n8n-nodes-billionverify.billionVerify",
"typeVersion": 1,
"position": [
540,
300
],
"name": "Verify Email (BillionVerify)",
"credentials": {
"billionVerifyApi": {
"id": "",
"name": "BillionVerify account"
}
}
},
{
"parameters": {
"conditions": {
"options": {
"caseSensitive": true,
"leftValue": "",
"typeValidation": "loose"
},
"combinator": "and",
"conditions": [
{
"id": "is-deliverable",
"leftValue": "={{ $json.is_deliverable }}",
"rightValue": "",
"operator": {
"type": "boolean",
"operation": "true",
"singleValue": true
}
}
]
}
},
"type": "n8n-nodes-base.if",
"typeVersion": 2,
"position": [
720,
300
],
"name": "IF deliverable"
}
],
"connections": {
"When clicking ‘Test workflow’": {
"main": [
[
{
"node": "Get contacts",
"type": "main",
"index": 0
}
]
]
},
"Get contacts": {
"main": [
[
{
"node": "Verify Email (BillionVerify)",
"type": "main",
"index": 0
}
]
]
},
"Verify Email (BillionVerify)": {
"main": [
[
{
"node": "IF deliverable",
"type": "main",
"index": 0
}
]
]
},
"IF deliverable": {
"main": [
[
{
"node": "Send email",
"type": "main",
"index": 0
}
],
[]
]
}
},
"settings": {
"executionOrder": "v1"
}
}Workflow templates with Marketstack
Ready-to-use workflows that verify emails before Marketstack sends.
How it works
- 1
A user registers or subscribes to alerts in your Marketstack-powered application.
- 2
The email address is sent to BillionVerify via the REST API, n8n, or Integrately.
- 3
BillionVerify performs SMTP-level verification and checks for disposable or catch-all domain patterns.
- 4
The result is returned and used to either confirm the subscription or prompt the user for a valid address.
- 5
Verified subscribers receive consistent, reliable market data notifications without deliverability issues.
When to use this
Validate emails for stock alert subscriptions
When users subscribe to price alerts or market digests powered by Marketstack data, verify their email addresses first. Confirmed valid addresses mean your alerts reliably reach interested users.
Clean developer and API user registrations
Developers signing up for Marketstack API access often use work emails. BillionVerify confirms these are real, active inboxes — not catch-all corporate domains that silently discard messages.
FAQ
Why should a data API platform verify email addresses?
Even data-focused platforms send transactional emails — API keys, usage alerts, billing notices. Invalid emails mean these messages never arrive, creating support overhead and silent user drop-off.
How fast is the BillionVerify API?
Most verifications complete in under a second, making real-time validation at registration or subscription forms practical without affecting user experience.
Can BillionVerify detect catch-all corporate email domains?
Yes. BillionVerify specifically identifies catch-all domains — servers that accept all incoming mail regardless of whether the mailbox exists — and flags them so you can decide how to handle them.
Verify emails in Marketstack
Create a free account, grab your API key, and stop bounces before they happen.
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