Automatic verifications
Details on each automatic verification: email, phone, CNPJ, IP, and how to interpret the results.
Overview#
Every time a lead arrives in Zero Bad Leads, it goes through a series of automatic verifications before receiving a final score. Each verification analyzes a different aspect of the lead and contributes to the quality score.
The verifications run in parallel to ensure speed. On average, the entire process takes less than 3 seconds.
Email verification#
Email verification consists of three stages:
1. Format validation#
The system checks whether the email follows the standard RFC 5322 format (e.g., user@domain.com). Emails with spaces, invalid characters, or missing the @ symbol are rejected immediately.
2. MX record verification#
The system queries the MX (Mail Exchange) records of the email domain to confirm it can receive messages. If the domain has no MX records, the email is considered invalid.
3. Disposable email detection#
Temporary and disposable emails indicate low-quality leads. Zero Bad Leads maintains an up-to-date list of known disposable providers, including:
| Provider | Domain |
|---|---|
| Guerrilla Mail | guerrillamail.com |
| Mailinator | mailinator.com |
| TempMail | tempmail.com |
| YOPmail | yopmail.com |
| Throwaway | throwaway.email |
| TrashMail | trashmail.com |
| GetAirMail | getairmail.com |
| FakeInbox | fakeinbox.com |
| SharkLasers | sharklasers.com |
| Guerrilla Mail Block | guerrillamailblock.com |
The disposable provider list is continuously updated. If the email uses a disposable provider, the lead receives a significant score penalty.
Possible results#
| Result | Meaning |
|---|---|
| valid | Email with correct format, domain with MX records, and not disposable |
| invalid_format | Email with incorrect format |
| no_mx | Domain has no MX record |
| disposable | Email from a disposable provider |
Phone verification#
E.164 normalization#
The system automatically converts the phone number to the international E.164 format. For Brazilian numbers, the country code +55 is added automatically.
Normalization examples:
| Input | E.164 Result |
|---|---|
| (11) 99999-9999 | +5511999999999 |
| 11999999999 | +5511999999999 |
| +55 11 99999-9999 | +5511999999999 |
| 99999-9999 | Invalid (missing area code) |
Country code detection#
For Brazilian leads, the system automatically identifies the country code +55. If the number already contains an international code, it is preserved.
Format validation#
The system verifies whether the number has the correct number of digits for the detected country. For Brazil:
- Mobile: 11 digits (area code + 9 + 8 digits) — e.g., 11 9 9999-9999
- Landline: 10 digits (area code + 8 digits) — e.g., 11 3333-3333
If your lead does not include the area code, the phone number will be marked as invalid. Make sure your forms request the full number with area code.
Possible results#
| Result | Meaning |
|---|---|
| valid | Phone successfully normalized with correct format |
| invalid | Invalid format or incorrect number of digits |
| missing | Phone field not submitted |
CNPJ verification#
CNPJ verification uses the BrazilAPI to query public data from the Brazilian Federal Revenue Service (Receita Federal).
How it works#
When the lead contains a CNPJ field (or the system detects a CNPJ in the submitted data), a query is made to BrazilAPI to obtain company information.
Extracted data#
| Field | Description |
|---|---|
| Legal Name | Official legal name of the company |
| Trade Name | Commercial name of the company |
| Company Size | Company size (MEI, ME, EPP, others) |
| Registration Status | Current status with the Federal Revenue Service |
| Incorporation Date | Date the company was established |
| Primary CNAE | Main economic activity |
If the CNPJ registration status is not "Active", the lead receives a score penalty. Companies with "Closed", "Suspended", or "Unfit" status are considered high risk.
Possible results#
| Result | Meaning |
|---|---|
| valid | CNPJ found with "Active" status |
| invalid | CNPJ with invalid format |
| inactive | CNPJ found but status is not "Active" |
| not_found | CNPJ not found in the Federal Revenue database |
| missing | CNPJ field not submitted |
IP verification#
IP verification uses ProxyCheck.io to assess the risk associated with the lead's IP address.
What is verified#
- Risk score: value from 0 to 100 indicating the probability of the IP being malicious
- Proxy: whether the IP is associated with a proxy server
- VPN: whether the IP is being used by a VPN
Interpreting the risk score#
| Score | Level | Interpretation |
|---|---|---|
| 0–10 | Low | Clean IP, no risk indicators |
| 11–30 | Moderate | Some minor indicators, generally safe |
| 31–60 | Elevated | Possible proxy or VPN usage, requires attention |
| 61–80 | High | Strong indication of proxy, VPN, or suspicious activity |
| 81–100 | Very high | IP associated with abuse, spam, or fraud |
How the IP affects the score#
| Situation | Score impact |
|---|---|
| Clean IP (0–10) | No penalty |
| Moderate risk IP (11–30) | Light penalty |
| Elevated risk IP (31–60) | Moderate penalty |
| Proxy detected on IP | Additional penalty |
| VPN detected on IP | Additional penalty |
| High risk IP (61+) | Severe penalty |
IP verification depends on the IP address being sent along with the lead data. If the IP is not available, this verification is simply skipped and does not negatively affect the score.
How verifications affect the final score#
The lead's final score (0 to 100) is calculated by artificial intelligence taking into account all the verifications above, plus the ideal lead profile you configured.
The verifications work as signals:
- Positive signals: valid email, valid phone, active CNPJ, clean IP
- Negative signals: disposable email, invalid phone, inactive CNPJ, IP with proxy/VPN
The AI combines these signals with your scoring profile criteria to generate the final score. The more positive signals, the higher the score.
You can view the result of each verification individually on the lead details page. This helps you understand exactly why a lead received a particular score.
Related articles
How qualification works
Understand the automatic qualification pipeline: email, phone, CNPJ validation, IP analysis, and AI scoring.
Lead Details
How to view and interpret detailed lead information, including score, verifications, and history.
Configure scoring profile
Learn how to configure your ideal lead profile using AI conversation or ready-made templates.