Reduce Email Bounce Rate by 85%: Proven Methods

Email bounce rates silently destroy marketing campaigns, damage sender reputation, and waste valuable resources. When emails bounce, they don't just fail to reach recipients—they trigger a cascade of negative consequences that compound over time. ISPs interpret high bounce rates as a signal of poor list quality, leading to increased spam filtering and reduced inbox placement for all your emails. This comprehensive guide reveals proven methods that have helped organizations reduce their email bounce rates by 85% or more, transforming their email marketing effectiveness and protecting their sender reputation. For foundational concepts, see our complete guide to email verification.

Understanding Email Bounce Rates

Before implementing bounce reduction strategies, understanding the mechanics of email bounces helps identify the most impactful interventions.

What is Email Bounce Rate

Email bounce rate measures the percentage of sent emails that fail to deliver and return to the sender. This metric directly reflects your email list quality and impacts your overall email marketing success.

The bounce rate calculation is straightforward: divide the number of bounced emails by the total number of emails sent, then multiply by 100. For example, if you send 10,000 emails and 500 bounce, your bounce rate is 5%.

Industry benchmarks vary, but generally, bounce rates above 2% indicate problems requiring immediate attention. Best-in-class email programs maintain bounce rates below 0.5%, while rates above 5% can trigger ISP penalties and blacklisting.

Hard Bounces vs Soft Bounces

Understanding the difference between hard and soft bounces is crucial for implementing effective reduction strategies, as each type requires different handling.

Hard bounces occur when emails permanently fail to deliver due to invalid addresses, non-existent domains, or blocked recipients. These addresses should be immediately removed from your list as they will never become deliverable. Common causes include typos in email addresses, deleted accounts, and non-existent domains.

Soft bounces represent temporary delivery failures where the address might be valid but the message couldn't be delivered at that moment. Causes include full mailboxes, temporary server issues, or message size limits. Soft bounces may resolve on retry, but addresses that consistently soft bounce should eventually be treated as hard bounces.

The True Cost of High Bounce Rates

High bounce rates impose costs far beyond the immediate failed deliveries. Understanding these costs motivates investment in proper email verification and list hygiene.

Sender reputation damage is the most significant hidden cost. ISPs track bounce rates as a key quality signal, and consistently high bounces lead to lower inbox placement rates across your entire email program. Once damaged, sender reputation takes months to rebuild.

Financial costs include wasted marketing spend on messages that never reach recipients, reduced ROI from email campaigns, and potential costs from ESP penalties or required plan upgrades due to list quality issues.

Opportunity costs accumulate as poor deliverability means missed connections with customers who might have converted, engaged, or made purchases if they had received your emails.

Root Causes of Email Bounces

Identifying the specific causes of your bounces enables targeted interventions that maximize impact.

Data Entry Errors

Human error during email collection is one of the largest sources of invalid addresses. Users mistype addresses, forget characters, or enter intentionally fake addresses. Studies show that 20-30% of manually entered email addresses contain errors.

Common typos include transposed letters (gmial instead of gmail), missing characters (yahoo.com vs yahooo.com), and wrong domain extensions (.con instead of .com). These errors are preventable with real-time validation during collection.

Natural List Decay

Email addresses naturally become invalid over time as people change jobs, abandon accounts, or switch email providers. Industry data suggests that email lists decay at approximately 22-30% annually, meaning a list that was 100% valid will have significant invalid addresses within a year.

Corporate email lists decay faster than consumer lists because job changes immediately invalidate work email addresses. B2B marketers must be especially vigilant about list maintenance.

Purchased or Rented Lists

Lists acquired from third parties consistently produce high bounce rates and other deliverability problems. These lists often contain outdated addresses, spam traps, and people who never consented to receive your emails.

Beyond bounce rates, using purchased lists risks severe ISP penalties, legal consequences under regulations like GDPR and CAN-SPAM, and permanent damage to sender reputation that affects all your email sending.

Inactive Subscribers

Subscribers who stop engaging eventually become bounce risks. While their addresses may still exist, ISPs may recycle dormant addresses into spam traps, or the accounts may become abandoned and eventually deleted.

Proactively managing inactive subscribers through re-engagement campaigns and eventual removal prevents these addresses from becoming bounce sources.

Email Verification: Your Primary Defense

Email verification is the most effective single intervention for reducing bounce rates, capable of eliminating 80-90% of potential bounces before they occur.

How Email Verification Reduces Bounces

Professional email verification services like BillionVerify check addresses across multiple dimensions before you attempt delivery. This prevents bounces by identifying invalid addresses proactively rather than learning about them through failed sends.

The verification process includes syntax validation to catch malformed addresses, DNS and MX record verification to confirm domains can receive email, SMTP verification to check if specific mailboxes exist, and detection of disposable, role-based, and problematic addresses.

By verifying addresses before sending, you eliminate the primary cause of hard bounces—invalid addresses—from your campaigns entirely.

Implementing Verification at Collection Points

The most cost-effective time to verify emails is at the point of collection. Real-time verification prevents invalid addresses from ever entering your database, maintaining list quality from the start. Learn more about implementing email verification during signup.

// Real-time email verification during signup
async function validateSignupEmail(email) {
  // Quick syntax check first
  if (!isValidEmailSyntax(email)) {
    return {
      valid: false,
      message: 'Please enter a valid email address format'
    };
  }

  try {
    // Call BillionVerify API for comprehensive validation
    const response = await fetch('https://api.billionverify.com/v1/verify', {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${process.env.EMAILVERIFY_API_KEY}`,
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({ email })
    });

    const result = await response.json();

    if (!result.deliverable) {
      // Provide helpful feedback based on the reason
      let message = 'This email address cannot receive emails';

      if (result.is_disposable) {
        message = 'Please use a permanent email address';
      } else if (result.reason === 'invalid_domain') {
        message = 'This email domain does not exist';
      } else if (result.suggestion) {
        message = `Did you mean ${result.suggestion}?`;
      }

      return { valid: false, message };
    }

    return { valid: true };
  } catch (error) {
    // On API error, allow submission but flag for later verification
    console.error('Verification API error:', error);
    return { valid: true, needsVerification: true };
  }
}

Bulk List Cleaning

For existing lists, bulk verification identifies and removes invalid addresses before they can bounce. This is essential when you acquire a new list, haven't sent to a list in months, or notice increasing bounce rates.

// Bulk email list verification workflow
async function cleanEmailList(emails) {
  const results = {
    valid: [],
    invalid: [],
    risky: [],
    unknown: []
  };

  // Process in batches to respect API limits
  const batchSize = 1000;
  for (let i = 0; i < emails.length; i += batchSize) {
    const batch = emails.slice(i, i + batchSize);

    const response = await fetch('https://api.billionverify.com/v1/verify/batch', {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${process.env.EMAILVERIFY_API_KEY}`,
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({ emails: batch })
    });

    const batchResults = await response.json();

    batchResults.forEach(result => {
      if (result.deliverable && result.quality_score >= 80) {
        results.valid.push(result.email);
      } else if (!result.deliverable) {
        results.invalid.push({
          email: result.email,
          reason: result.reason
        });
      } else if (result.is_catch_all || result.quality_score < 80) { // See: /blog/catch-all-email-detection
        results.risky.push({
          email: result.email,
          score: result.quality_score,
          isCatchAll: result.is_catch_all
        });
      } else {
        results.unknown.push(result.email);
      }
    });

    // Rate limiting between batches
    await new Promise(resolve => setTimeout(resolve, 1000));
  }

  return results;
}

Verification Frequency Recommendations

Different list segments require different verification frequencies based on their decay rates and risk profiles.

For subscriber lists that receive regular campaigns, verify quarterly at minimum. Lists with higher-value segments or those used for important communications should be verified monthly.

Transactional email lists should be verified whenever a hard bounce occurs, with periodic full-list verification to catch addresses that have become invalid between sends.

Lists that haven't been mailed in over 90 days should be fully verified before any campaign, as significant decay will have occurred during the dormant period.

List Hygiene Best Practices

Beyond verification, comprehensive list hygiene practices prevent bounce rates from climbing over time.

Regular List Maintenance Schedule

Establish a routine maintenance schedule that includes immediate removal of hard bounces after each campaign, weekly review of soft bounces with removal of addresses that have soft bounced multiple consecutive times, monthly suppression of inactive subscribers based on engagement metrics, and quarterly verification of the entire list.

// Automated list hygiene workflow
class ListHygieneManager {
  constructor(options = {}) {
    this.hardBounceThreshold = options.hardBounceThreshold || 1;
    this.softBounceThreshold = options.softBounceThreshold || 3;
    this.inactivityDays = options.inactivityDays || 180;
  }

  async processPostCampaign(campaignResults) {
    const actions = {
      removed: [],
      suppressed: [],
      flagged: []
    };

    for (const result of campaignResults) {
      if (result.bounceType === 'hard') {
        // Immediately remove hard bounces
        await this.removeSubscriber(result.email, 'hard_bounce');
        actions.removed.push(result.email);
      } else if (result.bounceType === 'soft') {
        // Track soft bounces
        const bounceCount = await this.incrementSoftBounceCount(result.email);

        if (bounceCount >= this.softBounceThreshold) {
          await this.removeSubscriber(result.email, 'repeated_soft_bounce');
          actions.removed.push(result.email);
        } else {
          actions.flagged.push({
            email: result.email,
            bounceCount
          });
        }
      }
    }

    return actions;
  }

  async identifyInactiveSubscribers() {
    const cutoffDate = new Date();
    cutoffDate.setDate(cutoffDate.getDate() - this.inactivityDays);

    const inactive = await db.subscribers.findAll({
      where: {
        lastEngagement: { $lt: cutoffDate },
        status: 'active'
      }
    });

    return inactive;
  }

  async runReengagementCampaign(inactiveSubscribers) {
    // Tag subscribers for re-engagement
    for (const subscriber of inactiveSubscribers) {
      await subscriber.update({
        reengagementStarted: new Date(),
        reengagementStatus: 'pending'
      });
    }

    // Trigger re-engagement email sequence
    await emailService.sendReengagementSeries(inactiveSubscribers);
  }

  async removeSubscriber(email, reason) {
    await db.subscribers.update({
      status: 'removed',
      removedReason: reason,
      removedAt: new Date()
    }, {
      where: { email }
    });

    // Add to suppression list
    await db.suppressionList.create({
      email,
      reason,
      addedAt: new Date()
    });
  }
}

Managing Soft Bounces Effectively

Soft bounces require nuanced handling because they may resolve on retry. However, addresses that consistently soft bounce should be treated as problematic.

Implement a soft bounce counter that tracks consecutive soft bounces per address. After 3-5 consecutive soft bounces across different campaigns, move the address to a suppression list. This prevents wasting resources on addresses that are effectively undeliverable while giving temporary issues time to resolve.

Sunset Policy for Inactive Subscribers

Inactive subscribers who haven't opened or clicked emails in extended periods represent hidden bounce risks. ISPs may recycle dormant addresses, and even if the address remains valid, zero engagement signals to ISPs that your emails may not be wanted.

Implement a sunset policy that defines engagement thresholds and timeframes. A typical policy might suppress subscribers after 6 months of no opens and 12 months of no clicks, with a re-engagement attempt before final removal.

// Sunset policy implementation
async function applySunsetPolicy() {
  const now = new Date();

  // Identify candidates for re-engagement (3-6 months inactive)
  const reengagementCandidates = await db.subscribers.findAll({
    where: {
      lastOpen: { $lt: new Date(now - 90 * 24 * 60 * 60 * 1000) },
      lastOpen: { $gt: new Date(now - 180 * 24 * 60 * 60 * 1000) },
      status: 'active',
      reengagementStatus: null
    }
  });

  // Identify candidates for removal (6+ months inactive, re-engagement failed)
  const removalCandidates = await db.subscribers.findAll({
    where: {
      lastOpen: { $lt: new Date(now - 180 * 24 * 60 * 60 * 1000) },
      status: 'active',
      reengagementStatus: 'completed',
      reengagementResponse: false
    }
  });

  return {
    forReengagement: reengagementCandidates,
    forRemoval: removalCandidates
  };
}

Technical Configuration for Deliverability

Proper technical setup ensures your emails are authenticated and trusted by receiving servers.

SPF Record Configuration

Sender Policy Framework (SPF) records tell receiving servers which IP addresses are authorized to send email for your domain. Missing or incorrect SPF records can cause emails to be rejected or marked as spam.

Your SPF record should include all services that send email on your behalf, including your email service provider, marketing platforms, and transactional email services.

v=spf1 include:_spf.google.com include:sendgrid.net include:mailchimp.com ~all

DKIM Implementation

DomainKeys Identified Mail (DKIM) adds a cryptographic signature to your emails, allowing receiving servers to verify the message wasn't modified in transit. DKIM authentication significantly improves deliverability.

Generate DKIM keys through your email service provider and add the public key to your DNS records. Most ESPs provide specific instructions for their DKIM implementation.

DMARC Policy

Domain-based Message Authentication, Reporting & Conformance (DMARC) builds on SPF and DKIM to provide instructions to receiving servers on how to handle authentication failures. DMARC also enables you to receive reports on authentication results.

Start with a monitoring policy to gather data before enforcing:

v=DMARC1; p=none; rua=mailto:dmarc-reports@yourdomain.com; pct=100

After analyzing reports and ensuring legitimate email passes authentication, gradually move to quarantine and eventually reject policies for maximum protection.

Content Optimization for Deliverability

Email content affects deliverability in ways that indirectly impact bounce rates through reputation effects.

Avoiding Spam Triggers

Content that triggers spam filters damages sender reputation, which in turn affects bounce handling. Avoid common spam triggers including excessive capitalization, multiple exclamation points, spam-associated phrases, and suspicious link patterns.

// Content spam score checker
function analyzeContentRisk(subject, body) {
  const risks = [];
  let score = 0;

  // Check subject line
  if (/[A-Z]{4,}/.test(subject)) {
    risks.push('Excessive capitalization in subject');
    score += 10;
  }

  if (/!{2,}/.test(subject)) {
    risks.push('Multiple exclamation points');
    score += 10;
  }

  // Check body content
  const spamPhrases = [
    'act now', 'limited time', 'click here', 'free gift',
    'no obligation', 'winner', 'congratulations', 'urgent'
  ];

  const lowerBody = body.toLowerCase();
  spamPhrases.forEach(phrase => {
    if (lowerBody.includes(phrase)) {
      risks.push(`Spam phrase: "${phrase}"`);
      score += 5;
    }
  });

  // Check link ratios
  const linkCount = (body.match(/https?:\/\//g) || []).length;
  const wordCount = body.split(/\s+/).length;

  if (linkCount > wordCount / 50) {
    risks.push('High link-to-text ratio');
    score += 15;
  }

  return {
    score,
    risks,
    recommendation: score > 30 ? 'High risk - revise content' :
                    score > 15 ? 'Moderate risk - review flagged items' :
                    'Low risk'
  };
}

Maintaining Engagement

High engagement signals to ISPs that recipients want your emails, improving your reputation and reducing the likelihood that future bounces will trigger penalties.

Segment your list to send relevant content to each group. Personalize beyond just the name to include relevant offers and content. Test send times to find when your audience is most likely to engage.

Monitoring and Analytics

Continuous monitoring enables early detection of bounce rate increases before they cause significant damage.

Key Metrics Dashboard

Track these metrics to maintain visibility into email deliverability health:

// Email deliverability metrics tracking
class DeliverabilityMetrics {
  async getDashboardMetrics(dateRange) {
    const campaigns = await db.campaigns.findAll({
      where: {
        sentAt: {
          $gte: dateRange.start,
          $lte: dateRange.end
        }
      }
    });

    const metrics = {
      totalSent: 0,
      totalDelivered: 0,
      totalBounced: 0,
      hardBounces: 0,
      softBounces: 0,
      totalOpens: 0,
      totalClicks: 0,
      bounceRate: 0,
      deliveryRate: 0,
      openRate: 0,
      clickRate: 0
    };

    campaigns.forEach(campaign => {
      metrics.totalSent += campaign.sent;
      metrics.totalDelivered += campaign.delivered;
      metrics.totalBounced += campaign.bounced;
      metrics.hardBounces += campaign.hardBounces;
      metrics.softBounces += campaign.softBounces;
      metrics.totalOpens += campaign.opens;
      metrics.totalClicks += campaign.clicks;
    });

    metrics.bounceRate = (metrics.totalBounced / metrics.totalSent * 100).toFixed(2);
    metrics.deliveryRate = (metrics.totalDelivered / metrics.totalSent * 100).toFixed(2);
    metrics.openRate = (metrics.totalOpens / metrics.totalDelivered * 100).toFixed(2);
    metrics.clickRate = (metrics.totalClicks / metrics.totalDelivered * 100).toFixed(2);

    return metrics;
  }

  async getBounceBreakdown(dateRange) {
    const bounces = await db.bounces.findAll({
      where: {
        occurredAt: {
          $gte: dateRange.start,
          $lte: dateRange.end
        }
      }
    });

    const breakdown = {
      byType: { hard: 0, soft: 0 },
      byReason: {},
      byDomain: {},
      trend: []
    };

    bounces.forEach(bounce => {
      // By type
      breakdown.byType[bounce.type]++;

      // By reason
      breakdown.byReason[bounce.reason] = (breakdown.byReason[bounce.reason] || 0) + 1;

      // By domain
      const domain = bounce.email.split('@')[1];
      breakdown.byDomain[domain] = (breakdown.byDomain[domain] || 0) + 1;
    });

    return breakdown;
  }
}

Alert Thresholds

Set up automated alerts when bounce rates exceed acceptable thresholds:

// Bounce rate alerting system
async function checkBounceAlerts(campaignId) {
  const campaign = await db.campaigns.findById(campaignId);

  const bounceRate = campaign.bounced / campaign.sent * 100;

  const alerts = [];

  // Warning threshold
  if (bounceRate >= 2 && bounceRate < 5) {
    alerts.push({
      level: 'warning',
      message: `Campaign bounce rate is elevated: ${bounceRate.toFixed(2)}%`,
      recommendation: 'Review recent list additions and consider verification'
    });
  }

  // Critical threshold
  if (bounceRate >= 5) {
    alerts.push({
      level: 'critical',
      message: `Campaign bounce rate is critical: ${bounceRate.toFixed(2)}%`,
      recommendation: 'Pause sending and verify list immediately'
    });

    // Automatically pause scheduled campaigns
    await pauseScheduledCampaigns();
  }

  // Domain-specific issues
  const domainBounces = await analyzeDomainBounces(campaignId);
  for (const [domain, rate] of Object.entries(domainBounces)) {
    if (rate > 10) {
      alerts.push({
        level: 'warning',
        message: `High bounce rate for ${domain}: ${rate.toFixed(2)}%`,
        recommendation: `Investigate ${domain} addresses in your list`
      });
    }
  }

  // Send alerts
  for (const alert of alerts) {
    await sendAlert(alert);
  }

  return alerts;
}

Case Study: Achieving 85% Bounce Rate Reduction

Understanding how organizations achieved dramatic bounce rate reductions provides a roadmap for implementation.

Initial Assessment

A mid-sized e-commerce company was experiencing 8% bounce rates, causing deliverability problems and ISP blocking. Their list of 500,000 subscribers had been built over 5 years with minimal verification or hygiene practices.

Analysis revealed 15% of addresses had obvious syntax issues or invalid domains, 12% of valid-looking addresses failed SMTP verification, 8% were disposable or role-based addresses, and 25% of subscribers hadn't engaged in over a year.

Implementation Strategy

The remediation followed a phased approach over 3 months:

Phase 1 focused on list verification and cleaning. The entire list was verified through BillionVerify's bulk verification API. Hard invalids (15%) were immediately removed. Risky addresses (catch-alls, low scores) were segmented for special handling.

Phase 2 implemented re-engagement and sunset policies. Subscribers inactive for 180+ days received a 3-email re-engagement sequence. Non-responders (60% of inactive) were suppressed. Active re-engagers were returned to main segments.

Phase 3 established ongoing prevention measures. Real-time verification was added to all signup forms. Double opt-in was implemented for high-risk channels. Monthly verification schedules were established. Automated bounce processing was deployed.

Results Achieved

After full implementation, bounce rates dropped from 8% to 1.2%—an 85% reduction. Inbox placement rates improved from 72% to 94%. Email ROI increased by 45% due to better deliverability and list quality. Customer support tickets related to "didn't receive email" decreased by 60%.

The total list size decreased by 35%, but active, engaged subscribers actually increased as improved deliverability meant more legitimate subscribers received and engaged with emails.

Advanced Strategies

Beyond basics, advanced strategies provide additional bounce rate optimization.

Predictive Bounce Prevention

Machine learning models can predict which addresses are likely to bounce based on historical patterns, engagement metrics, and address characteristics.

// Simple predictive bounce scoring
function calculateBounceRiskScore(subscriber) {
  let score = 0;

  // Engagement factors
  const daysSinceLastOpen = (Date.now() - subscriber.lastOpen) / (1000 * 60 * 60 * 24);
  if (daysSinceLastOpen > 180) score += 30;
  else if (daysSinceLastOpen > 90) score += 15;
  else if (daysSinceLastOpen > 30) score += 5;

  // List age
  const daysOnList = (Date.now() - subscriber.joinedAt) / (1000 * 60 * 60 * 24);
  if (daysOnList > 365) score += 10;
  if (daysOnList > 730) score += 10;

  // Previous bounce history
  if (subscriber.softBounceCount > 0) score += subscriber.softBounceCount * 10;

  // Email domain risk
  const domain = subscriber.email.split('@')[1];
  if (isHighRiskDomain(domain)) score += 15;

  // Verification recency
  const daysSinceVerification = subscriber.lastVerified
    ? (Date.now() - subscriber.lastVerified) / (1000 * 60 * 60 * 24)
    : 365;
  if (daysSinceVerification > 180) score += 20;
  else if (daysSinceVerification > 90) score += 10;

  return {
    score,
    risk: score > 50 ? 'high' : score > 25 ? 'medium' : 'low',
    factors: generateRiskFactors(subscriber, score)
  };
}

Segment-Based Sending Strategies

Not all subscribers need the same sending approach. Segment your list based on engagement and risk levels, then apply appropriate strategies to each segment.

High-engagement, low-risk subscribers can receive full campaign frequency. Medium-engagement subscribers might receive reduced frequency with only the best content. High-risk subscribers should be verified before each campaign and receive only the most critical communications.

Feedback Loop Integration

Register for ISP feedback loops to receive notifications when recipients mark your emails as spam. This data helps identify and remove subscribers who don't want your emails before they start bouncing.

// Process feedback loop reports
async function processFeedbackLoop(report) {
  for (const complaint of report.complaints) {
    // Remove from active list
    await db.subscribers.update({
      status: 'complained',
      complainedAt: new Date(),
      complainedCampaign: report.campaignId
    }, {
      where: { email: complaint.email }
    });

    // Add to permanent suppression
    await db.suppressionList.create({
      email: complaint.email,
      reason: 'spam_complaint',
      source: report.isp
    });

    // Log for analysis
    await analytics.track('spam_complaint', {
      email: hashEmail(complaint.email),
      campaignId: report.campaignId,
      isp: report.isp
    });
  }
}

Measuring Success

Track progress toward bounce rate reduction goals with appropriate metrics and benchmarks.

Key Performance Indicators

Primary KPIs for bounce rate management include overall bounce rate (target below 2%, ideal below 0.5%), hard bounce rate (target 0%), soft bounce rate (monitor for patterns), and inbox placement rate (target above 90%).

Secondary KPIs that indicate list health include list growth rate minus churn, engagement rates (opens, clicks), complaint rates (target below 0.1%), and unsubscribe rates (monitor for unusual spikes).

Benchmarking Progress

Compare your metrics against industry benchmarks and your own historical performance. Document your starting point and track improvement over time.

Create monthly reports showing bounce rate trends, verification results, list composition changes, and engagement metrics. Use this data to refine your strategies and demonstrate ROI on email verification investments.

Conclusion

Reducing email bounce rates by 85% or more is achievable through systematic implementation of email verification, list hygiene practices, and technical optimization. The key is treating bounce rate management as an ongoing process rather than a one-time fix.

Start with professional email verification to eliminate the largest source of bounces—invalid addresses. Implement proper list hygiene practices to prevent decay from accumulating. Configure technical authentication to maximize deliverability. Monitor continuously and respond quickly to emerging issues.

BillionVerify provides the comprehensive email verification tools needed to achieve and maintain low bounce rates. From real-time verification at collection points to bulk list cleaning and ongoing monitoring, BillionVerify's platform helps organizations protect their sender reputation and maximize email marketing effectiveness.

Take the first step toward dramatically lower bounce rates today. Sign up for BillionVerify and start verifying your email list with industry-leading accuracy and speed. For help choosing the right solution, see our best email verification service comparison.