Why self-hosted Reacher instead of a cloud API?

Self-hosted Reacher runs on your VPS at localhost:8080. Your email lists never leave your infrastructure. No third-party data exposure, no API rate limits, and faster response times (no network latency).

What does the 5-per-domain cap prevent?

Some SMTP servers have aggressive protection that triggers circuit breaker loops when too many verification requests hit the same domain. Capping at 5 emails per email domain prevents infinite retry cycles and protects your VPS IP reputation.

How accurate is SMTP verification?

SMTP handshake is the strongest single signal (+40 points) and is accurate for most domains. However, catch-all domains (which accept all addresses) and greylisting servers can produce false positives. That's why we use 8 checks together, not just SMTP alone.

What happens to TIER_3 emails?

TIER_3 (30-49) emails have inconclusive verification. We recommend manual review -- some are valid but behind catch-all domains or greylisting servers. They should not be included in cold outreach but may be valid for warm contacts.

Email Verification

8 checks. 4 tiers. Zero guesswork.

Syntax -> DNS -> SMTP -> Catch-All -> Disposable -> Role -> Auth -> Reacher

Every email scored 0-100 with full transparency into why. Not a black box -- you see exactly which checks passed and failed. Self-hosted Reacher on VPS for maximum speed and zero third-party data exposure. SQLite caching means re-verification is instant.

Verification Checks

Confidence Tiers

200

Concurrent Workers

0-100

Score Range

Email Verification

Live

+95%

1,847

Verified

123

Review

+3%

89%

Tier 1

Verification Results

j.smith@acme.com95TIER_1

m.jones@startup.io82TIER_1

info@example.com45TIER_3

h.wong@enterprise.co88TIER_1

The Cost of Sending to Unverified Emails

Bounce rates above 3% damage sender reputation and trigger spam filters

Disposable and role-based addresses waste campaign budget with zero engagement

Catch-all domains mask invalid addresses -- you think the email works but it bounces

Verification services expose your email lists to third-party data brokers

API rate limits on cloud services create bottlenecks during large verification runs

No distinction between 'definitely invalid' and 'probably valid' leads to all-or-nothing decisions

Self-Hosted, Transparent, Tiered

Eight independent checks, weighted scoring, and a self-hosted Reacher instance that keeps your data private.

8 Independent Checks

Syntax (RFC 5322), DNS/MX lookup, SMTP handshake, catch-all detection, disposable domain check, role-based filter, DKIM/SPF/DMARC analysis, and Reacher fallback.

Weighted Scoring (0-100)

SMTP handshake (+40), MX records (+20), auth records (+15), Reacher confirm (+10), pattern match (+10), reputation (+15). Full weight breakdown visible per email.

SQLite Cache

Previously verified emails return instantly from cache. No duplicate SMTP connections. Cache invalidation on configurable TTL.

Self-Hosted Reacher

Reacher runs on your VPS at localhost:8080. No email data leaves your infrastructure. No third-party API rate limits.

4-Tier Classification

TIER_1_SEND (80+), TIER_2_LIKELY_GOOD (50-79), TIER_3_REVIEW (30-49), SKIP (<30). Actionable tiers for send decisions.

Circuit Breaker Protection

Domains with aggressive SMTP protection auto-trigger circuit breakers. Cap at 5 emails per domain prevents infinite retry loops.

Verification Pipeline

Each stage processes data sequentially with full checkpoint/resume capability.

Step 1

Syntax Validation

RFC 5322 format check. Reject malformed addresses before any network calls. (+5 points)

Step 2

DNS/MX Lookup

Verify domain exists and has mail exchange records configured. (+20 points)

Step 3

SMTP Handshake

Connect to mail server, issue RCPT TO command, verify mailbox exists without sending. (+40 points)

Step 4

Catch-All Detection

Test with random address to determine if domain accepts all emails regardless of mailbox. (+5 points)

Step 5

Disposable Domain Check

Check against database of temporary/throwaway email services (Guerrilla Mail, Temp Mail, etc.). (+5 points)

Step 6

Role-Based Filter

Detect info@, admin@, support@, sales@, hr@ addresses. Flag but don't reject -- some role addresses are valid targets. (+5 points)

Step 7

DKIM/SPF/DMARC Analysis

Verify domain has email authentication records configured. Indicates legitimate email infrastructure. (+15 points)

Step 8

Reacher Fallback

Self-hosted Reacher provides secondary verification for ambiguous results. Confirms deliverability. (+10 points)

Technical Workflow

# Verify a CSV of emails (50 concurrent workers)
python -m tools.email_verifier --input leads.csv --workers 50

# Verify with higher concurrency
python -m tools.email_verifier --input leads.csv --workers 200

# REST API mode (port 8100)
python -m tools.email_verifier --api --port 8100

# Pre-verification checklist (MANDATORY):
# 1. Cap at 5 emails per email domain
# 2. Remove noreply@*, no-reply@*, hosting@gabia.com
# 3. Run cleanup_contacts.py first
# 4. Output path MUST be .csv

# Reacher self-hosted on VPS at $VPS_HOST:8080
# Config: /opt/reacher/backend_config.toml

API Access

POST

/api/v1/verify

Verify a single email. Returns score (0-100), tier, and individual check results.

POST

/api/v1/verify/batch

Batch verify up to 1,000 emails. Returns scores, tiers, and per-email check details.

GET

/api/v1/verify/{email}/status

Check verification result from cache. Returns cached score or 'not_verified'.

GET

/api/v1/verify/stats

Verification statistics: total verified, tier distribution, cache hit rate.

Use Cases

Pre-Campaign Verification

Verify your entire email list before launching outbound campaigns. Remove SKIP tier to prevent bounces.

CRM Hygiene

Periodically verify CRM emails to remove invalid addresses and update confidence scores.

Lead Scoring Input

Use verification tier as a lead scoring signal. TIER_1 contacts are higher priority than TIER_3.

Real-Time Verification

API mode for verifying emails at point of capture -- web forms, imports, and integrations.

Email List Cleaning

Clean purchased or scraped email lists before use. Remove disposable, role-based, and invalid addresses.

Deliverability Protection

Continuous verification to catch emails that become invalid over time (job changes, domain expiry).

Industry Applications

SaaS / Technology

High email volume, reputation-sensitive sending infrastructure.

Marketing Agencies

Client email lists requiring quality assurance before campaigns.

Financial Services

Regulatory compliance requires verified contact data.

Manufacturing

Trade show email lists need verification before follow-up.

Performance Metrics

95%+

TIER 1 Deliverability

Emails scoring 80+ deliver reliably

200

Concurrent Workers

Parallel verification for large lists

<0.5s

Cached Results

Previously verified emails return instantly

Independent Checks

Each contributes weighted points to final score

Platform Preview

See how LeadsLogix processes, verifies, and delivers your leads in real time.

LeadsLogix Dashboard

Live

+12%

24,847

Leads

+8%

18,293

Verified

+15%

6,142

Companies

+22%

$2.8M

Pipeline

Pipeline78%

Discover

Crawl

Extract

Verify

Score

Verification Dashboard

Tier distribution chart, cache hit rates, and per-domain verification status.

Pipeline Engine

Live

Active Pipeline2,847 records

Discover

100%

Crawl

100%

Extract

87%

Verify

64%

Score

42%

ETA: 12 min remainingProcessing...

Email Detail View

Individual email with all 8 check results, score breakdown, and tier classification.

Email Verification

Live

+95%

1,847

Verified

123

Review

+3%

89%

Tier 1

Verification Results

j.smith@acme.com95TIER_1

m.jones@startup.io82TIER_1

info@example.com45TIER_3

h.wong@enterprise.co88TIER_1

Batch Results

Color-coded verification results with export options for each tier.

Integrations

Salesforce

HubSpot

Pipedrive

Mailgun

SendGrid

Amazon SES

REST API

CSV Export

Verify before you send

Every email scored 0-100 with full transparency. Self-hosted verification keeps your data private. No third-party exposure.

FAQ

Frequently Asked Questions

Everything you need to know about our platform.

Still have questions?

Our team can walk you through the pipeline, pricing, and your use case.

Talk to us

Related Workflows

Email Finder Pipeline

Product

Find emails before verifying

/products/email-finder

Contact Validation

Product

Full contact data validation

/products/contact-validation

Email Deliverability

Product

Optimize sending reputation

/products/email-deliverability

Email Intelligence System

Complete email intelligence overview

/email-intelligence

# Verify a CSV of emails (50 concurrent workers) python -m tools.email_verifier --input leads.csv --workers 50 # Verify with higher concurrency python -m tools.email_verifier --input leads.csv --workers 200 # REST API mode (port 8100) python -m tools.email_verifier --api --port 8100 # Pre-verification checklist (MANDATORY): # 1. Cap at 5 emails per email domain # 2. Remove noreply@*, no-reply@*, hosting@gabia.com # 3. Run cleanup_contacts.py first # 4. Output path MUST be .csv # Reacher self-hosted on VPS at $VPS_HOST:8080 # Config: /opt/reacher/backend_config.toml