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Customer data validation

Add contact checks and consistent formatting to signup forms, onboarding flows, and CRM integrations. Use email, phone, and postal-code APIs to help users correct records before those records move through your product.

API documentationPlans and pricing

Recommended APIs

Start with the endpoints your feature needs. Each API includes documentation and sample requests.

Validate Email
Email format and domain DNS checks, plus disposable-address and domain metadata.
Validate Phone
Number validity, country context, and national, international, and E.164 formats.
Postal Code
Postal-code lookups with city, region, and coordinates where covered.
Disposable Email Checker
A focused disposable-domain check when that is the only signal your workflow needs.

Integration workflow

Turn inconsistent contact details into structured records that your application can use more consistently.

  1. Validate fields when they matter

    Check email and phone details when users finish entering them or submit a form. Call the APIs from your backend and return field-specific feedback without exposing your API key.

  2. Normalize and enrich the record

    Use returned phone formats for consistent storage, and look up postal-code location context where supported. Treat multiple postal matches as choices for the user rather than silently assigning an address.

  3. Apply your product’s rules

    Decide whether an invalid field blocks submission or requests a correction. Route uncertain results for review, handle temporary API failures separately, and preserve the values needed by downstream CRM or support workflows.

Example workflow

Input
An email, phone number, and postal code
API data
Validity checks + normalized formats + location context
Product output
A customer record with actionable field feedback

Example request

Start with an email check

The response includes is_valid and domain metadata. Use the documented checks to decide how to present feedback; this endpoint does not send a verification email.

curl --request GET \ 'https://api.api-ninjas.com/v1/validateemail?email=info%40api-ninjas.com' \ --header 'X-Api-Key: YOUR_API_KEY'

Replace YOUR_API_KEY with your API key. See the endpoint documentation for parameters and response fields.

Production considerations

Separate validity from verification

A correctly formatted email with DNS records does not prove mailbox ownership or delivery. A valid phone number does not prove it is active or belongs to the user. Add a verification step if your product needs that assurance.

Use location data at the right level

Postal-code lookup provides location context, not proof that a street address is deliverable. Check country coverage and let users confirm the details used in their customer record.

Handle temporary failures

A timeout is not an invalid customer record. Give users a retry or review path appropriate to your workflow, and distinguish API errors from failed validation checks.

Plans and usage

Estimate request volume from the number of customer records and checks per record, including retries and repeat submissions. Compare plans for request capacity, technical support, and vendor-onboarding documentation.

Use the free plan to evaluate supported endpoints. API and historical-data access vary by plan.

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Frequently asked questions

Can I add one check to an existing application?
Yes. Each API works independently. Start with an email check in your signup flow, for example, and add phone or postal data only when your product needs it.
Does email validation guarantee that a message will arrive?
No. The Validate Email API checks formatting and domain DNS records and returns additional metadata. It does not guarantee inbox delivery or verify that a person controls the mailbox.
How do I integrate these APIs into a CRM cleanup workflow?
Process records through the relevant endpoints, track uncertain results separately, and size your subscription for the request volume.
Does API Ninjas retain the customer details I submit?
API Ninjas has a zero-data-retention policy for API inputs and outputs. See the policy for details. Your application remains responsible for how it collects, stores, and uses customer records.

Related resources

Other use cases