Sending Limits & Retry Policy
Understand ESP rate limits during relay lane migration, IP lane warmup limits, and Laneful's retry policies.
All email providers have rate limits
Automatic retry for failed deliveries
On this page
Overview
During relay lane migration, your existing ESP's rate limits govern throughput. During IP lane warmup, sending volume increases gradually over 2-6 weeks. Laneful automatically handles retries and queueing throughout both phases.
How Laneful Handles Limits
Automatic Queueing: When a provider hits its limit, Laneful queues your emails and sends them as capacity becomes available.
Smart Retry: If any SMTP relay rejects messages due to rate limits or temporary errors, Laneful retries delivery for up to 3 days.
Failover: In tracks with multiple lanes, traffic automatically shifts to available lanes when others reach capacity.
Provider-Specific Limits
Each email provider has different limits. Here's what you need to know:
Relay Lane ESP Limits (Migration Period)
Relay lanes are free and route through your existing ESP during IP warmup. The ESP you are migrating away from governs throughput until migration is complete. Relay lanes are removed once your IP lanes are fully warmed.
Common ESP Rate Limits
- • SendGrid: Varies by plan (40K+ emails/month on paid plans)
- • Mailgun: Varies by plan
- • AWS SES: Sandbox: 200/day; Production: scales with reputation
Laneful's Handling
- • Queues email when ESP limit is hit
- • 3-day retry policy for failed sends
- • Progressively shifts traffic to IP lanes as they warm
AWS SES Limits
Sandbox Mode
- • 200 emails per 24 hours
- • 1 email per second
- • Only verified emails
- • Must request production access
Production Mode
- • Starts at 200 emails/day
- • Automatically increases with good reputation
- • Can reach millions per day
- • Very cost-effective at scale
IP Lane Limits
New IP Addresses: Start with low limits (50-100 emails/day) and gradually increase based on reputation signals. Laneful's AI handles this automatically.
Warmed IP Addresses: Can handle millions of emails per month with up to 20 concurrent connections to ISPs.
ISP-Specific Limits: Each ISP (Gmail, Outlook, Yahoo) has different acceptance rates and connection limits.
Laneful's Retry Policy
When emails can't be delivered immediately, Laneful automatically retries using an intelligent backoff strategy.
How Retries Work
Initial Attempt
Email is sent to the provider's SMTP server immediately.
Rejection/Error
Provider rejects due to rate limits, temporary errors, or quota exceeded.
Intelligent Retry
Laneful queues the email and retries with exponential backoff for up to 3 days.
Retry Schedule
What Triggers Retries
Permanent Failures (No Retry)
Some errors are permanent and won't be retried:
Planning Your Email Volume
Use these guidelines to plan your email sending and avoid delays:
IP Lane Warmup Timeline
Weeks 1-2: Low volume — new IP addresses start at 50-100 emails/day and build reputation gradually.
Weeks 3-4: Volume scales as ISPs confirm positive reputation signals. Relay lane handles overflow.
Weeks 5-6: IP lanes reach full capacity. Relay lane is removed. All traffic flows through your dedicated IPs.
Campaign Timing Strategies
Spread Throughout Day
- • Avoid hitting daily limits quickly
- • Better for provider reputation
- • Allows for urgent emails later
Schedule Large Campaigns
- • Split large lists across multiple days
- • Use Laneful's scheduling features
- • Monitor delivery rates and adjust
Monitoring & Alerts
Laneful provides tools to monitor your sending limits and delivery status:
Dashboard Metrics
Automatic Alerts
AI Agent Insights
Laneful's AI agent continuously monitors your sending patterns and provides proactive recommendations:
Best Practices
Follow these practices to optimize your email delivery within provider limits:
✓ Do
- • Monitor your sending patterns and adjust campaigns
- • Use scheduling to spread large campaigns over time
- • Set up alerts for rate limit warnings
- • Test with small volumes before scaling up
- • Keep track of daily/monthly usage across all channels
- • Plan for growth with appropriate lane types
✗ Don't
- • Send all emails at once without considering limits
- • Ignore rate limit warnings or queue buildups
- • Assume provider limits won't affect your use case
- • Mix high-priority transactional with bulk marketing
- • Forget about limits when planning campaigns
Ready to Optimize Your Sending?
Understanding limits is just the first step. Learn how to configure your lanes and implement best practices for reliable email delivery.