Automate quality gates
Call verification when contacts are created so teams are not limited to occasional dashboard checks.
Email validation API
Email Validation API for Application Integrations
Integrate Lucenri into your own applications with a REST/JSON workflow: send an authenticated request, let the crystal verification engine review the address, and receive structured status categories your code can map to product decisions—without promising inbox delivery.
New accounts currently receive 250 welcome credits.
Application
- REST API
- JSON Responses
- Secure Authentication
- Clear Status Categories
- API Access*
- 250 Welcome Credits
*API access is available on eligible plans.
Why use an Email Validation API
When address quality matters at the moment of signup, import, or automation, an API embeds verification into your software—consistent, testable, and closer to where data is created.
Keep decisions inside your product
Map status categories to accept, review, or reject policies you control in application code.
Scale beyond manual workflows
Pair programmatic single checks with list-oriented routes when automation volume grows—while operators can still use Bulk Email Verification for file work.
Stay consistent across tools
The same crystal verification engine powering Lucenri’s product can feed CRM hooks, onboarding services, and internal tools.
API philosophy
Lucenri returns structured decision-support—readable status categories and supporting checks—not a black-box score as the primary story, and never a delivery guarantee.
Readable status categories
Branch on clear statuses such as valid, invalid, disposable, or catch_all instead of inventing opaque thresholds alone.
Understandable outcomes
Engineers and operators can share one vocabulary between API responses and product decisions.
Transparent supporting detail
Checks and severity help explain signals. Confidence may appear as a supporting numeric field—not a substitute for status policy.
What we refuse to claim
No magic AI theater, no “100% confidence,” and no guaranteed inbox placement. Decision support, spoken carefully.
How the API works
The integration story stays aligned with Lucenri’s crystal verification engine: application request in, refraction through checks, structured JSON out.
Application needs a judgment
A signup service, CRM job, or automation is ready to evaluate one or more addresses.
Send an authenticated API request
POST JSON to the single validation path with auth (API key header or product JWT path) from a trusted server.
Crystal verification engine
Lucenri applies layered verification signals and normalizes a result object for that address.
Receive structured JSON
A success envelope includes the result and remaining credit balance context after a successful single check.
Your application decides
Map status to accept, review, enrich, or block according to your own product policy.
Authentication
Use authenticated product identity on verification routes. Integrators typically send an API key header from a server environment.
API key header
Send x-api-key with a key that starts with lcr_. Do not embed real keys in public client code.
JWT session or Bearer
The product also accepts authenticated JWT via secure session cookie or Authorization: Bearer—useful for panel-connected workflows.
Verified email for keys
API key authentication requires a verified account email. Complete verification in Lucenri before relying on key-based calls.
Eligible plans
API access is available on eligible plans. Start free, then review account options inside the product.
Request example
Pedagogical illustration of a single validation request. Field names match the product contract; use placeholders—never live secrets.
Headers (server-side environment)
Content-Type: application/json
x-api-key: $LUCENRI_API_KEYJSON body
{
"email": "[email protected]"
}Load $LUCENRI_API_KEY from a server environment variable or secret store. Never ship API keys in browser bundles or public client code.
Response example
A successful single check returns a JSON envelope with a normalized result. Status is primary; confidence is supporting detail only.
Envelope
success: true
Status
valid
Policy
Your app maps status → action
Illustrative success body
{
"success": true,
"result": {
"email": "[email protected]",
"valid": true,
"status": "valid",
"severity": "success",
"code": "ok-valid",
"confidence": 92,
"checks": [
{ "step": "syntax", "result": "pass", "code": "chk-syntax-ok" }
]
},
"balance": 249
}Exact confidence and checks vary by address and available signals. This sample illustrates shape and field names—not a fixed accuracy claim.
Status categories
Build policies around the product’s readable status taxonomy. Labels are machine strings—display them clearly in human interfaces.
- validStrong positive signals for the address at check time
- invalidNot dependable as a usable contact based on layered signals
- disposableTemporary or throwaway provider signals
- roleRole-style addresses (e.g. shared inboxes)
- typoPossible domain or address typo patterns
- catch_allMailbox confirmation uncertainty on accept-all domains
- riskyElevated risk or caution signals
- unknownInsufficient confirmation—review carefully
For interactive single-address literacy, see Email Checker. Specialty depth lives on Disposable Email Checker and Catch-All Email Checker.
When things fail
Errors should be both human-readable and machine-parseable. Design callers for explicit failure paths—not silent fallbacks.
Readable messages
Failed responses typically include success: false and an error string such as “Valid email required” or “Insufficient credits”.
Actionable classes
Plan for authentication gaps, insufficient credits, invalid input, and temporary service issues. Recover with clearer operator messaging.
No vague black boxes
Log the envelope. Surface the message to operators when needed. Avoid inventing undocumented error catalogs on this landing page.
Illustrative error envelope
{
"success": false,
"error": "Valid email required"
}Typical integration journey
A calm path from first account to production use—without promising multi-language SDKs or public docs that are not yet published.
-
Sign up
Create a Lucenri account. New accounts currently receive 250 welcome credits.
-
Generate an API key
Create or view product API keys after email verification. Keys use the
lcr_prefix. -
First request
Call single validation from a trusted server using JSON and the API key header.
-
Receive JSON
Parse the envelope, read
result.status, and log supporting fields. -
Integrate into the application
Place the call at signup, CRM writes, import jobs, or support tools—matching your risk policy.
-
Go live carefully
Keep secrets in server configuration, handle errors, and watch credit balance as usage grows.
Where teams integrate
Embed decision support where data is born—without framing verification as aggression or guaranteed reachability.
Signup forms
Gate registration quality when durable contact data matters.
CRM and lead capture
Cleaner inventories when contacts enter sales systems.
Marketing automation
Decision support before campaign inclusion—not a delivery promise.
Support portals
Reduce unreachable requesters at ticket creation.
SaaS onboarding
Quality-check invites and workspace contacts programmatically.
Customer imports
Run automated list validation; use Bulk Email Verification when operators prefer files.
Frequently asked questions
What is an email validation API?
An email validation API is an HTTP interface your software calls to check an address and receive structured, machine-readable results. Your application decides what to do next—accept, review, store, or reject—based on clear status categories rather than manual dashboard clicks alone.
How does the Lucenri email validation API work?
Your application sends an authenticated request. Lucenri’s verification engine reviews the address through layered checks and returns a JSON envelope with a normalized result object, including status categories your code can map to product policy.
How do I authenticate?
Integrations commonly use an API key in the x-api-key header. Keys use the lcr_ prefix. Lucenri also supports authenticated JWT session or Bearer token paths used by the product application. API key use requires a verified account email.
What format is returned?
JSON is the primary response format. Successful single checks return a success flag, a result object, and credit balance context where applicable. Error responses use success set to false with a human-readable error message.
Does the API guarantee delivery?
No. Lucenri provides decision-support signals for address quality and risk. Validation does not guarantee delivery or inbox placement.
Can I validate one email via API?
Yes. The single validation path accepts one email address in a JSON body and returns a structured result for that address. New accounts currently receive 250 welcome credits to help you start.
How is the API different from Bulk Email Verification?
Bulk Email Verification is the product workflow for human operators: upload CSV or TXT, review, and download. The API is for applications that call verification programmatically—including single checks and list-oriented routes when you scale automation.
How do credits work?
Verification requests consume product credits according to your account balance. New accounts currently receive 250 welcome credits on signup. Manage credits and plans inside the Lucenri product after you start free.
Is the API available on every plan?
API access is available on eligible plans. Start free to explore the product with welcome credits, then review plan options inside Lucenri for your team’s needs.
What status categories can appear?
Results use readable status values such as valid, invalid, disposable, role, typo, catch_all, risky, and unknown. Map those categories to your application policy. Numeric confidence may appear as a supporting field and is not a delivery guarantee.
What do error responses look like?
Errors return JSON with success set to false and a readable error message—for example when a valid email is required, credits are insufficient, or authentication is missing. Design your integration to handle failures explicitly.
Where is full developer documentation?
This page is a commercial and educational overview. For endpoint contracts, authentication, limits, and result schemas, use the API reference and OpenAPI JSON.
How is this different from Email Checker?
Email Checker is the interactive single-address experience for human review. The Email Validation API is for applications that integrate the same crystal verification engine via HTTP and structured JSON.
Should I call the API from the browser with an API key?
No. Keep API keys on trusted server environments. Do not expose lcr_ keys in public front-end code or ship secrets in client bundles.
Start integrating with calmer decisions
Create a free account, review credits, and connect authentication from your server—then map structured status categories to the policies that make sense for your product.