Throttled Again? Learn the Proven Strategies to Smooth Out Your Email Delivery

Does your email suddenly get delayed and drip in? Do bounced emails and spam complaints spike mysteriously? You may be getting throttled. Learn what causes it, how to confirm you’re affected, proven techniques to prevent throttling, and tips to recover when it strikes. After reading this complete guide, you’ll understand how to keep your emails flowing smoothly to the inbox.

Email throttling refers to limiting the number of emails a sender can deliver over a period of time. While outright blocking prevents all emails from being sent, throttling allows some emails through but imposes restrictions on volume.
Throttling is a way for email providers to manage strained resources and curb behaviors that threaten deliverability for everyone. If you’ve ever tried sending a bunch of emails too fast and received error messages like “exceeds sending limits”, you’ve experienced throttling firsthand!

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What Exactly is Throttling?

Throttling works by establishing sending thresholds and temporarily limiting excess traffic. Common forms of throttling include:

  • Rate limiting – Restricting the number of emails per minute or hour. For example, 100 emails per hour. Emails beyond the threshold are deferred or bounced until the period resets.
  • Connection limiting – Limiting the number of simultaneous connections to a server. This controls resource usage.
  • Recipient limiting – Limiting the number of emails to a domain or recipient. Helps curb spam complaints.
  • Reputation-based – Stricter limits based on sender reputation to better protect deliverability. Spammers get throttled more aggressively.

Throttling applies delays and restrictions, rather than outright blocking all emails. Legitimate bulk senders are impacted, but well-behaved sending practices can avoid or minimize it.

Throttling vs Blocking

It’s important to distinguish throttling from blocking:

Blocking is more severe and reserved for serious violations or threats identified by an email provider. Some clear signs of blocking include immediate bouncebacks regardless of volume and error messages explicitly stating your account has been disabled for policy violations.

With throttling, emails will slow down but not stop entirely. You may only notice intermittent issues when sending above normal levels. Understanding these differences helps identify the root cause.

Why Do Providers Throttle Email?

There are a few primary reasons providers throttle senders:

1. To Manage Strained Resources

Throttling prevents overuse of email infrastructure like servers, storage, and processing capacity. By limiting volumes based on resources, providers can offer service to more customers. Think of it like a freeway managing rush hour traffic flow by controlling the pace of entering vehicles.

2. To Maintain Deliverability

Reputation is critical for delivering to the inbox. Throttling helps curb behaviors that threaten deliverability for everyone:

3. To Encourage Good Sending Practices

Throttling incentivizes senders to follow best practices that align with ethical, sustainable email delivery:

  • List quality – Keeping lists clean minimizes bounces and complaints. Throttling prevents overuse of dirty lists.
  • Relevance – Well-targeted, engaged audiences help build sender reputation. Throttling discourages irrelevant mass blasting.
  • Infrastructure investment – Throttling encourages proper infrastructure to manage higher volumes smoothly.

The best approach is optimizing campaigns to avoid triggering throttles in the first place. But some throttling will always occur as part of maintaining a healthy email ecosystem. Understanding these reasons can help inform strategies.

Email throttling doesn’t always make itself obvious. You may only notice intermittent issues or a vague feeling that delivery isn’t as smooth as it should be.
But by recognizing the common signs of throttling, you can identify and confirm when it’s occurring. This visibility helps diagnosis the root cause and determine appropriate next steps.

Indicators for Throttling

Here are the top indicators to monitor that can signal your emails are being throttled:

1. Increased Bounce Rates

Bounce rates are one of the clearest signs of potential throttling issues.

Hard bounces occur when emails permanently fail to reach recipients. Common reasons include invalid addresses or domains that reject all messages.

Throttling bounces have a distinct pattern:

  • Intermittent spikes in bounce rates, correlated to sending volume or cadence.
  • Bounce rate spikes may only occur when sending above normal levels.
  • Most bounces are temporary soft bounces rather than permanent hard bounces.
  • Once sending volumes decrease, bounce rates stabilize again.

This trend of volume-correlated bouncing indicates the provider is likely throttling above a certain sending threshold. Troubleshooting to identify the specific rate or volume limits can help inform mitigation strategies.

2. Increase in Spam Complaints

Sudden spikes in spam complaints can also suggest throttling may be occurring.

Recipients report emails as spam for many reasons – irrelevant content, suspicious behavior, or messages mistakenly filtered to the spam folder then marked as spam.

With throttling, higher complaint rates often correlate to:

  • Sending larger email volumes or at higher frequency.
  • Emails being delayed, so they arrive out of expected order. Recipients may see this as suspicious.
  • Sudden use of new sending IP addresses without proper warmup.

Monitoring for complaint spikes correlated to major sending changes is wise. Throttling’s impact on reputation means extra vigilance here.

3. More Emails Going to the Spam Folder

Another clue is increasing percentages of your emails getting trapped in spam folders rather than the inbox.

Due to throttling delays, messages may arrive scattered over longer periods. Spam filters pay attention to odd delivery patterns as a potential signal.

Higher spam folder rates may emerge under these throttling scenarios:

  • Sending large volumes over short durations.
  • Using new IP addresses without adequate warmup.
  • Significant delays between batch sends.
  • Requests to unsubscribe or mark as not spam being throttled.

If recipients must frequently retrieve your emails from spam, take heed. Their engagement may suffer, and spam complaints often follow.

4. Delayed Email Delivery

Perhaps the most straightforward and noticeable effect of throttling is delayed delivery.

Normally most messages arrive quickly – within minutes or a few hours at most. But under heavy throttling, delays extend dramatically further:

  • Emails may trickle over hours or days rather than sending promptly.
  • Messages often arrive out of sequence compared to when they were sent.
  • Delivery delays likely correlate to increased sending activity.
  • Restarting your computer or waiting may seem to briefly resolve the issues until hitting limits again.

Robust email providers queue messages during throttling so eventual delivery remains reliable. But extended delays create headaches for senders and recipients alike.

5. Error Messages Indicating Throttling

Finally, error messages offer the most explicit confirmation that throttling is happening and provide insight into where limits are being imposed:

  • SMTP service unavailable – The email server is actively throttling connections.
  • Exceeds sending limits – Surpassing account-level or domain sending limits.
  • Deferred – Queued temporarily to smooth delivery during throttling.
  • Throttling on reputation – Confirms reputation-based throttling in effect.
  • Specific rate or quantity thresholds – Indicates usage above defined limits.

These messages may appear inconsistently during spikes in traffic. But if you see them emerge regularly when sending higher volumes, take note.

Staying aware of potential throttling indicators helps respond quickly when issues emerge. Keeping delivery smooth requires vigilance, but a few simple monitoring steps go a long way.

Impact of Throttling

Email throttling can severely impact email delivery and campaign performance if sender practices aren’t adapted. Understanding the potential fallout empowers you to prioritize avoiding and recovering from throttling scenarios.
While throttling doesn’t outright block all email, its effects compound over time:

1. Lower Inbox Placement Rates

Throttling’s delays confuse spam filters, leading to more messages filtered as spam or promotions. Slow delivery and non-linear sequences appear suspicious.

Recipients that frequently have to retrieve your emails from spam folders will train filters further. Even when you resolve the root cause, those reinforced filter habits persist.

Aggressive throttling trains filters so aggressively that inbox placement suffers long-term. Consistent inbox delivery requires meticulous reputation management.

2. Decreased Email Deliverability

With inboxes harder to reach, overall email deliverability and recipient experience declines.

Deliverability refers to emails reliably arriving in recipients’ inboxes quickly. But throttling has several counterproductive effects:

  • Delayed delivery – Messages trickle inconsistently over extended durations.
  • Lower reach – More messages filtered as spam mean fewer touchpoints.
  • Redundant sending – Resending messages already queued wastes resources.
  • Poor user experience – Recipients must check spam folders and reassemble non-chronological threads.

Throttling’s drag on deliverability grows over time as problems compound. Careful delivery planning prevents this.

3. Damaged Sender Reputation

Throttling is essentially a consequence of already-damaged sending reputation. But it exacerbates issues further through additional complaints and filters continually reinforced.

Reputation accounts for factors like:

  • Complaint rates – Complaint spikes from throttling encourage more aggressive throttling.
  • Bounce rates – Hard bounces signal issues costing you reputation. Throttling drives more soft bounces.
  • Spam folder rates – Filters systematically diverting emails hurt reputation.
  • Unsubscribe requests – Throttling delays opt-outs, causing more complaints.

With reputation diminished, not only do throttling limits tighten, but inbox filters grow more skeptical of messages as well.

4. Reduced Engagement Metrics

Between deliverability suffering and strained recipient experiences, email engagement metrics also predictably decline due to aggressive throttling:

Frequent aggressive throttling conditions recipients to tune out your messages. Nurturing engagement requires avoiding these scenarios.

In Summary, the Costs of Unchecked Email Throttling Include:

  • Worse inbox placement and deliverability over time
  • More emails filtered to spam or promotions
  • Significant damage to critical sender reputation
  • Loss of recipient goodwill through poor experiences
  • Lower open, click, and conversion rates
  • Less ROI from underperforming emails
  • Greater costs recovering from damaged reputation

Avoiding throttling ensures your long-term ability to connect with audiences and drive business value through email. Be proactive, because recovery is difficult.

Types of Throttling

Email providers leverage a variety of advanced techniques to identify and throttle potential spam. Understanding these detection methods helps illustrate why certain best practices are effective at avoiding aggressive throttling.

Let’s explore the primary ways providers identify spammy behavior and throttle its impact:

Volume-Based Throttling

One of the simplest yet most essential throttling techniques is volume control.

By rate limiting the number of outgoing emails per account and tracking usage, huge spikes in sending raise flags. Volume limits help mitigate potential issues from large spam runs.

Typical volume-based throttling practices include:

  • Rate limiting emails per second, minute, hour, or day based on package thresholds.
  • Limiting connection concurrency by individual IP and account.
  • Restricting new sent emails if unsent queue builds up excessively.
  • Lower volume thresholds for known spammers or risky senders.
  • More generous thresholds for reputable senders with good metrics.

The specific volume limits aren’t usually publicized. But monitoring your traffic patterns and watching for correlated throttling provides approximations.

Content Analysis

Email providers also utilize content analysis to detect characteristics commonly associated with spam and throttle accordingly:

  • Keyword stuffing – Excessive keyword density triggers spam suspicion. Throttling discourages overuse.
  • Suspicious links – Redirects, obfuscated URLs, hidden tracking, and blacklisted sites imply malicious intent. Messaging with risky links sees tighter restrictions.
  • Deceptive subject lines – Misleading or dishonest subject lines annoy recipients and lead to spam complaints when expectations don’t match content. Providers throttle accounts using manipulative subject lines.
  • Text analysis – NLP models profile normal language patterns vs automated or copied content. Unusual text statistics may warrant throttling as spammers avoid original writing.
  • Data leaksEmail lists from data breaches are more likely to churn spam complaints. Known risky lists can be subject to preemptive throttling.

Scrutinizing content helps identify high-risk patterns most associated with spamming. Targeted throttling curbs potential abuse.

Reasons for Throttling

Behavioral Analysis

Looking at the performance of sent email provides further signals for managing throttling:

  • Complaint rates – Accounts generating more spam complaints or opt-out requests see tighter limits to incentivize cleaner lists.
  • Unsubscribe requests – Excessive unsubscribes imply poor targeting or irrelevant messaging. Throttling prevents over-sending.
  • Spam folder rates – Having large percentages filtered as spam indicates poor reputation, and throttling minimizes further impact.
  • Low engagement – Very low open and click rates signal ineffective messaging that wastes resources. Limits encourage more deliberate sending.

Ongoing analysis of real-world email metrics shapes appropriate throttling to optimize for engaged recipients.

IP Reputation

In addition to account-level controls, IP-based reputation also informs throttling:

  • Blacklists – IPs on spam blacklists are more aggressively throttled and monitored to avoid full blocks.
  • ISP complaint rates – IPs drawing high complaint levels from major ISPs may be restricted.
  • Past sending – IPs with histories of spam or policy violations are often preemptively limited.
  • Associated accounts – Shared IPs used heavily for spamming face stricter limits.
  • Benchmarks – IPs exhibiting unusual spikes from established baselines trigger throttling reviews.

Since IPs can be shared by many senders, their reputations determine baseline assumptions that enable appropriate throttling.

Machine Learning Models

Finally, advanced ML models represent the future of predictive email throttling:

  • Anomaly detection – Models profile normal traffic patterns to flag unusual account activity warranting throttling reviews.
  • Spam classification – ML classifiers analyze content and metadata to systematically identify spammy messages for restriction.
  • Complaint prediction – Models estimate complaint probability for each send to limit potential abuse proactively.
  • Embedded metrics – Embedding models directly into infrastructure for real-time automated throttling of risky traffic.
  • Personalized limits – Models customize ideal throttling thresholds per account based on unique attributes.

Machine learning provides a scalable solution to spam threats by flagging high-risk activity for targeted throttling.

How to avoid getting Throttled

Avoiding Keyword Stuffing

One notorious spam technique is keyword stuffing – packing as many popular keywords into content as possible to game searches and filters.

This causes problems:

  • Keyword density far exceeds natural language.
  • Readability suffers from awkward phrasing.
  • Recipients sense manipulation rather than helpful content.
  • Getting filtered as spam defeats the purpose anyway!

Maintain keyword density under 3-5% with a natural, conversational writing style instead. Prioritize delivering real value, and throttles will remain laissez-faire.

Ensuring Quality Contact Lists

Many spamming issues arise from low-quality purchased email lists. Lists filled with:

  • Inactive or invalid emails.
  • Users that never opted in.
  • Mismatched demographics and interests.

This causes headaches:

  • High bounce rates from bad addresses.
  • Angry recipients who complain and mark messages as spam simply for being unexpected.
  • Low open and click rates from irrelevant audiences.

Invest in carefully confirming opt-ins and nurturing engaged subscriber lists segmented by interest. It’s foundational to maintaining a healthy sending reputation and avoiding aggressive throttling.

Key Takeaways About How Providers Throttle Spam:

  • Analyzing volume, content, behaviors, reputation, and machine learning predictions enables nuanced throttling.
  • These methods pinpoint risky traffic for restrictions versus outright blocks.
  • Following best practices helps align with intended throttling of unengaged recipients and spam.
  • Avoiding keyword stuffing and maintaining strict list quality are two fundamental examples.

With holistic context, we see throttling helps sustain healthy email ecosystems. This benefits reputable senders willing to invest in deliverability.

How to recover after being Throttled

Once you recognize the signs of email throttling, the next step is addressing the root causes. Avoiding aggressive throttling boils down to honing sending reputation and aligning with receiver expectations.
Let’s explore proven techniques to uphold deliverability and prevent throttling:

Warm Up New IP Addresses

One of the most common throttle triggers is neglected IP warmup.

Brand new IPs lack sending history and reputation. As a result, major ISPs impose aggressive throttling until the IP earns trust:

  • No historical metrics – With no established volume or engagement baselines, providers cautiously limit new IPs.
  • No behavioral precedents – Lacking historical behavioral patterns, new IPs are assumed higher risk.
  • No linked domains – New IPs aren’t yet associated with established domain reputations from past sending.

Proper IP warmup introduces new IPs gradually, building positive metrics to ease throttling:

1. Start sending below typical volumes. New IPs should be ramped up from very low volumes to avoid sudden spikes that appear suspicious.

2. Warm up for at least 2 – 4 weeks. Send consistently at low but increasing volumes to establish positive metrics over an extended warmup period.

3. Prioritize highly engaged recipients. Target engaged test segments who are unlikely to complain or ignore messages.

4. Avoid major ISPs at first. Initially focus on low-risk domain recipients like Gmail and Yahoo while reputation improves.

5. Monitor throttling signals closely. Watch for any delivery delays, bounces, or other throttling indicators.

With a slow, metrics-focused IP warmup, your sending patterns become recognized as normal and non-threatening for that IP. This prevents harsh throttling.

Maintain High List Quality

Low email list quality is another fundamental throttle trigger. Bad lists lead directly to issues like:

  • High bounce rates – Invalid or mistyped addresses produce frustrating hard bounces.
  • Spam complaints – Recipients not expecting messages from you may report the emails as spam.
  • Low engagement – Irrelevant audiences won’t open or click, damaging deliverability metrics.

Use extreme diligence maintaining your lists by:

– Double opt-in subscription. Require recipients to confirm subscriptions to demonstrate intention. Avoid single opt-in where possible.

– Remove hard bounces promptly. Monitor for permanent bounces and remove undeliverable addresses to keep lists clean.

– Enable address updating. Make it easy for subscribers to update contact info if it changes.

– Segment by demographics. Send more relevant content by dividing broader lists into targeted interest groups.

– Prune inactive subscribers. Remove recipients that have not opened in 6+ months to focus on engaged users.

– Confirm frequently. Validate the list periodically by ensuring subscribers want to continue receiving content.

Investing in list quality signals responsible sending behavior that helps avoid throttling penalties.

Send During Optimal Times

Another easy optimization is timing your sends carefully:

– Avoid early mornings and nights when providers often perform maintenance that can interfere with delivery.

– Be consistent. Pick consistent days/times that recipients come to expect your emails to develop helpful patterns.

– Align with work habits. Focus on working hours for most business-related communications.

– Use regional insights. Factor in time zones and preferences when segmenting internationally.

– Consider weekends. For B2C emails, weekends can perform well and avoid crammed business inboxes.

– Spread campaigns. Spike traffic causes more throttling. Distribute volume in smaller batches over days.

– Avoid holidays. Inbox access dips during time off. Schedule fewer emails on holidays and Fridays.

With deliberate sending timing, traffic aligns with infrastructure capacity and engaged recipient availability.

Provide Valuable Content

Spam filters closely analyze content for signs of deception, manipulation, or automation. But meaningful content demonstrates responsible sending:

– Write original, personal copy. Avoid duplicated or synthetic-sounding language.

– Ensure relevancy. Recipients want content tailored to interests, not mismatched blasting.

– Prioritize value over conversions. Offer truly useful advice and insights without aggressive sales pitches.

– Respect the relationship. Understand subscribers signed up under certain pretenses. Meet expectations.

– Structure logically. Well-organized, coherent content is easier to parse and engages readers.

– Revise frequently. Continuously tweak and improve content based on feedback and analytics.

Recipients are far less likely to complain about or dismiss valuable emails targeted thoughtfully for them. Quality content signals your legitimacy.

Provide Convenient Opt-Out Options

Ethical messaging lets recipients leave anytime as subscribers’ circumstances change. But excess opt-outs can also trigger throttling reviews. The best approach:

– Include opt-out links. Provide one-click unsubscribe links in each email footer.

– Make preferences easy. Allow granular subscription management like interest selections.

– Avoid over-sending. Throttling often indicates sending too frequently. Give readers time to breathe.

– Personalize content. Disengagement often means content doesn’t resonate. Adapt and segment.

– Confirm opt-ins again. Reconfirming periodically helps clean lists of disinterested contacts gracefully.

– Part politely. Thank opt-outs for their past subscription and leave door open for future.

Best practice to avoid being Throttled again

Empowering recipients demonstrates respect and nurtures your reputation.

Use Authentication Methods

Email authentication protocols like DMARC, DKIM, and SPF verify your identity as a sender. Authentication confirms you’re not impersonating others, building trust:

Configure SPF records. Publish allowed sending IP addresses in DNS to match against.

– Add DKIM signatures. Cryptographically sign messages to validate authenticity.

– Enforce DMARC. Require receivers to check SPF/DKIM alignment and reject mismatches.

– Publish feedback reports. Learn authentication failures you need to address at scale.

– Adopt consistently. Apply protocols comprehensively across all messages and infrastructure.

Authentication demonstrates an investment in managing a controlled, ethical sending infrastructure less likely associated with malicious spamming.

Monitor Throttling Signals

Staying aware of throttle signals keeps you ahead of issues:

– Track bounce rate trends. Watch for volume correlated spikes.

– Review spam complaints. Check complaint figures before and after major sends.

– Audit spam folder rates periodically. Query recipients across ISPs.

– Note delivery delays. Do test sends encompass expected latency?

– Parse error messages. Errors often describe where limits are encountered.

– Document volume thresholds. Identify safe daily/hourly rates before throttling.

– Talk to your provider. Ask about recommendations to manage your reputation and avoid limits.

Ongoing visibility informs proactive solutions to smooth delivery and prevent throttling escalations.

Key Takeaways About Preventing Throttled Email:

  • Proper IP warmup, high-quality lists, optimal timing, great content, and authentication all help build sending reputation.
  • Providing opt-out options and monitoring signals show responsibility and focus on the recipient experience.
  • Patience and consistency over weeks or months are needed to strengthen deliverability durably.
  • Aligning with intended throttle targets for spam and disengaged recipients keeps your messages flowing smoothly.

With some time invested, any sender can learn to play nicely with throttling systems and enjoy ongoing inbox access.

Best Practices for Warming Up IPs

When warming up new IPs, take a slow and steady approach:

  • Send 50-100 emails per IP for the first few days.
  • Gradually increase volume by 20-50 emails sent per day.
  • It should take 2 to 4 weeks before ramping up to full desired volumes.
  • Avoid sending to major ISPs like Gmail, Outlook, or Yahoo at first. Prioritize smaller domains without advanced throttling.
  • Once volumes reach a few hundred per day successfully, cautiously expand to larger ISPs in low volumes.
  • Closely track throttling signals like spam complaints, delayed delivery, and unusual bounces. Stop immediately if issues emerge.
  • Use dedicated IPs rather than shared IPs to isolate your own sending reputation.

Taking 2-4 weeks to ramp up new IPs significantly reduces the risk of early throttling while building metrics.

Managing Contact Lists and Segmentation

Some key principles for maintaining high-quality contact lists:

  • Confirm all subscription opt-ins through double opt-in or explicit approval.
  • Import contacts only from trusted, legitimate sources rather than random online lists.
  • Segment contacts by interests, demographics, preferences, and behaviors to target content. Avoid spraying broadly.
  • Define an ongoing hygiene process, checking for inactive contacts, bounce removal, and periodic re-confirmation.
  • Make unsubscribes, opt-outs, and delivery issues easy to report. Remove contacts promptly upon request.
  • Encourage contacts to update their preferences and information to stay synchronized.
  • Review metrics regularly to identify underperforming segments for pruning or improved targeting.

Healthy list curation and segmentation keeps your content focused on receptive audiences less likely to complain or disengage.

Email Sending Strategies to Avoid Triggering Throttles

Some key strategies to keep email traffic smooth and avoid triggering harsh throttling:

  • Spread large campaign volumes over multiple days rather than massive single batch blasts.
  • Use smaller lists and segmented content to nurture relevance over mass spamming. Quality over quantity.
  • Maintain steady, consistent volumes day to day for better deliverability momentum. Spiky traffic raises flags.
  • Avoid sending during peak traffic periods for major ISPs, early morning and late afternoon.
  • Use APIs to monitor real-time traffic and pause sends if throttling or complaints spike alarmingly.
  • Temporarily slow traffic if throttling signs emerge to calm systems before resuming.
  • When re-engaging dormant subscribers, take extra time rewarming them to avoid surprises.
  • Review traffic shaping capabilities of your ESP that can smooth out batches automatically.

With a little volume management finesse, you can tiptoe around the harshest throttling landmines.

When to bring in an Expert and How they would fix it

Once throttling occurs, getting back to smooth deliverability requires diligence and patience. But with a concerted effort, you can undo the damage of excessive throttling over time.

Let’s explore proven techniques for recovering your sending capability after aggressive throttling:

Determine the Initial Cause

Before solving a throttling issue, it’s critical to diagnose the root cause:

  • Review traffic leading up to throttling spikes for usage spikes or changes.
  • Check if new IPs were introduced without proper warmup.
  • Audit email content for potential red flags like keyword stuffing.
  • Verify internal lists for data issues causing bounces.
  • Confirm external lists are cleanly opted-in and relevant.
  • Ensure authentication protocols are fully implemented.

Understanding what triggered the algorithms helps inform the best path to resolution.

Consult with Your Email Service Provider

Your ESP can provide guidance recovering from over-throttling based on your unique situation:

  • They have visibility into limitations imposed on your account.
  • They may share analysis of what factors influenced the throttling.
  • They know the nuances of their own systems and best practices.
  • They can confirm when throttling has been eased after improvements on your side.
  • Some even offer personalized consulting services to aid recovery.

This expertise helps calibrate your remediation plan to their expectations and feedback.

Warm Up Your Sending Reputation Again

The same IP and domain warmup fundamentals apply for rebuilding reputation after aggressive throttling:

  • Temporarily reduce volumes to well below normal levels. Start small.
  • Increase steadily in small increments as deliverability proves stable.
  • Watch metrics like spam complaints and latency closely. Pause if issues recur.
  • Expect to warmup for weeks or months, not days. There are no shortcuts.
  • Focus on your best subscriber segments first before expanding outreach.

With patient volume increases, you prove good behavior and earn back trust.

Improve Email Content and List Quality

Updating past problem areas prevents further issues:

  • Review content to ensure it provides authentic value and aligns with subscriber needs.
  • Confirm all lists are cleanly opted-in and segmented into targeted interests.
  • Aggressively prune inactive subscribers to focus on engaged users.
  • Limited test sends to small recipient samples can help gauge results.
  • Personalize and tailor future content based on improved understanding of your audience.

This realigns messaging with subscriber expectations to avoid further complaints.

Send More Personalized Email at Lower Volumes

Reigning in volume demonstrates deliberate, customer-focused sending:

  • Lower the cadence for any recurring email like newsletters. Give subscribers more time to engage rather than bombarding.
  • Segment broadly into granular interest groups with tailored content for each. Avoid spray-and-pray spamming.
  • Personalize subject lines and content using merge tags and transactional triggers. Show individual relevance.
  • Automate based on behaviors and preferences, only reaching out when there’s a clear personalized motivator to do so.
  • Monitor engagement closely, and continuously refine targeting as you learn.

Throttling is reduced when recipients consistently anticipate and appreciate your emails as valuable connections.

Key Principles for Recovering From Throttling:

  • Confirm the root cause, consult your ESP, and take time warming up carefully again.
  • Improve content quality and list management to realign with audience interests.
  • Send highly personalized and relevant emails in lower volumes.
  • Closely track engagement and delivery metrics for continuous optimization.
  • Expect the process to take weeks or months before full recovery.

With a thoughtful return to fundamentals, you can emerge better positioned than ever before.

Creating an Email Warmup Strategy

To develop an effective email warmup strategy:

  • Research recommended warmup volumes and pacing specific to your ESP.
  • Plot out a schedule ramping up from an initial 50-100 emails per day to your target volumes over 4+ weeks.
  • Focus initial emails on highly engaged current subscribers to build positive metrics.
  • Progressively expand to less engaged and cold segments as reputation improves.
  • Schedule warmup sends for regular business hours on Tuesday through Thursday when throttling is lighter.
  • Include a variety of content types like commercial promotions, informational content, transactional emails, etc.
  • Monitor throttling signals and complaints daily, adjusting pacing more conservatively if issues emerge.
  • Use warmup services to access established IPs if available through your ESP.

Deliberate planning ensures your warmup aligns with ESP expectations and best practices.

Safely Increasing Your Email Volume Again

When ramping volume back up after throttling issues:

  • Increase conservatively by no more than 25-50% each week.
  • If complaints or delays recur, hold volume flat for 1-2 weeks to stabilize.
  • When resuming increases, grow by smaller increments like 10-20% between hold periods.
  • Limit growth when approaching 60-75% of pre-throttle volumes until metrics prove solid.
  • Focus extra re-engagement efforts on dormant subscribers before large sends.
  • Randomize subject lines and content to avoid triggering filters watching for patterns.
  • Consult your ESP regularly for guidance aligning increases with their recommendations.

Cautious, metrics-driven pacing prevents recurrence of aggressive throttling.

Understanding Throttling Policies of Major ESPs

Understanding the nuances of major ESP throttling policies helps tailor sending approaches. Let’s overview some leading providers:

Overview of Throttling Policies

While providers keep exact throttling algorithms confidential, reviewing their guidance reveals useful insights:

  • Most confirm volume-based limits on sends per second, minute, hour, and day based on plan tiers. Exceeding thresholds triggers throttling.
  • Throttling is often reputation dependent, with riskier senders seeing tighter restrictions. Factors like complaints, bounces, and spam rate influence this.
  • Providers reduce throttling over time as you demonstrate good habits and warm up IPs properly. Constraints ease if problems subside.
  • Best practices are emphasized that align well with throttling systems, like list hygiene, sender authentication, quality content, etc. Adhering to recommendations helps avoid limits.
  • Support teams assist with troubleshooting and may provide advice if you encounter particular throttling issues. Their expertise is invaluable.

While frustrating at times, remember that responsible senders who closely follow all guidance see minimal disruption from throttling long-term.

SendGrid’s Throttling Policy

SendGrid implements algorithmic throttling to balance deliverability across their global customer base:

  • Throttling limits apply per account, mailbox provider, IP, and contact.
  • Constraints automatically adjust based on real-time traffic patterns and health metrics like bounces.
  • New accounts see more conservative limits until establishing positive metrics over time.
  • Proactive sender best practices are encouraged to boost reputation and minimize throttling. Dedicated IPs also help.

SendGrid notifies customers of potential issues that influence throttling like spam complaints. Their expertise helps navigate constraints.

MailChimp’s Throttling Policy

MailChimp leverages predictive machine learning to throttle potential spam:

  • Models analyze account and campaign factors to estimate abuse probability and throttle accordingly.
  • Content, links, user behaviors, complaint rates, authentication status, and volume all influence throttling probabilities.
  • Limits are not specified precisely but tighter restrictions are imposed on riskier activity.
  • Following recommended practices optimizes your “send reputation” score tracked by MailChimp to reduce throttling.

By voluntarily keeping your sending clean and aligned with subscriber interests, MailChimp allows more generous sending volumes.

Constant Contact’s Throttling Policy

Constant Contact imposes caps based on account pricing tiers:

  • Each plan has maximum sends per day, hour, and minute listed explicitly in their documentation.
  • Hitting account limits triggers identification and throttling to prevent abuse.
  • Reputation still influences throttling, with riskier accounts seeing tighter restrictions within their package thresholds.
  • New accounts also get access to lower starter volumes that ramp up over time as you prove reliable sending patterns.

Constant Contact’s public volume details help guide traffic planning, within the context of reputation factors.

Key Takeaways About Provider Throttling Policies:

  • Study your ESP’s specific guidance to understand their system and align your sending.
  • Volume, reputation, content quality, and authentication status are common throttling drivers.
  • Following recommended practices helps improve your send reputation and avoid undue limits.
  • Support teams can provide case-specific troubleshooting when you encounter throttling issues.

Frequently Asked Questions

Let’s wrap up with some frequently asked questions to solidify your understanding of email throttling best practices:

Why Do Companies Throttle Emails?

Providers throttle emails for a few core reasons:

  • To manage strained infrastructure and prevent overuse of shared resources. Throttling balances traffic.
  • To maintain high inbox placement and deliverability for all customers by restricting potential spam and abuse.
  • To incentivize good sending practices like list hygiene, authentication, and relevant content creation. Throttling guides senders.
  • To sustain email as an essential communication medium by ensuring continued receiver access.

Throttling acts as a necessary speed bump, not a roadblock. Following recommended practices smooths the ride.

How Do I Know If I’m Being Throttled?

Some signs your emails may be getting throttled:

  • Sudden spikes in bounce rates, correlated with increased sending
  • More spam complaints on higher volume emails or campaigns
  • Delivery delays of a few hours or even days for some messages
  • Emails going to spam folders more frequently
  • Error messages indicating limits exceeded
  • Inability to move the send queue despite low email volume

Monitoring key metrics and spikes relative to your sending patterns reveals potential throttling.

Is Throttling the Same as Blocking?

There are some key differences:

  • Throttling limits how quickly and how much you can send. Blocking stops all email traffic.
  • Throttling is temporary and adaptive. Blocking is complete and typically permanent.
  • Some emails get through when throttled. No emails are delivered when blocked.
  • Throttling is based on volume, rep, content, etc. Blocking follows serious policy violations.

Throttling imposes lighter constraints to mitigate issues versus outright termination of service.

Can Throttling Be Automatic?

Yes, throttling is often applied automatically based on:

  • Volume thresholds predefined based on plan sending limits
  • Reputation scores calculated from metrics like complaints, bounces, etc.
  • Analysis of content factors commonly associated with spam
  • Machine learning models predicting spam probability for each send

Automated throttling provides nimble response to protect deliverability, while allowing human review.

What Is Considered Bulk Email?

There’s no single definition, but some common bulk email traits:

  • Large recipient lists rather than individually targeted messages
  • Emphasis on quantity of sends over personalized quality
  • Focus on conversions or commercial promotion over deeper engagement
  • Generic content blasted broadly rather than tailored to specific audiences
  • Traffic driven by purchased lists rather than intentionally opted-in contacts
  • Tools and processes optimized for massive scaling over individualization

But diligent inbox placement, sender reputation, and quality experiences mean bulk email can be sent responsibly.

Other Common Questions About Email Throttling

What are the most common causes of throttling?

The leading triggers are high sending volumes, introducing new IPs without warmup, low email list quality, suspicious content, and anything else that risks deliverability if left unchecked.

How can I tell if my account is being throttled?

Watch for signs like delivery delays, increased bounces and spam complaints, more emails going to spam folders, and error messages indicating limits exceeded.

Do individual emails get throttled or just accounts?

Throttling can happen at the IP, account, and even individual email or recipient level based on real-time traffic and reputation analysis.

Is it possible to eliminate throttling completely?

Some degree will always occur during peak traffic times or reputation dips. But following best practices minimizes disruption from aggressive throttling long-term.

How long does it take to recover from heavy throttling?

Patience and consistently good habits over weeks or months are required to prove safe sending patterns and earn back full trust after issues.

What’s the difference between throttling and blocking?

Throttling temporarily slows traffic while blocking stops it completely. Throttling is more adaptive and based on various signals.

How do I know if my IP address has a poor reputation?

Indicators like immediate throttling of new IPs, stringent volume limits, or blocks after small incidents may suggest preexisting reputation problems.

What can I do if my email service provider won’t help with throttling issues?

Some providers offer personalizeddeliverability consulting. Warming up fresh IPs, improving content relevance, and verifying auth protocols help regardless.

How do I make my emails less likely to be throttled as spam?

Follow all best practices, avoid keyword stuffing, implement authentication protocols, closely monitor complaints and metrics for issues, and develop positive engagement habits over time.

While throttling feels inconvenient at times, remembering its purpose helps frame appropriate strategies to avoid undue disruption. With some diligence, your emails will flow smoothly.

Summary on Preventing and Recovering From Email Throttling

After reviewing fundamentals like what throttling is and why it happens, as well as actionable strategies to avoid and recover from issues, some core principles emerge:

  • Monitor key metrics like bounce rates, spam complaints, and delivery timing to recognize throttling signals early. Being proactive is key.
  • Follow best practices for inbox placement at all times regardless of sending volume, rather than cutting corners. This builds long-term deliverability.
  • Warm up new IPs gradually over weeks, avoid massive batch blasts, keep lists ultra clean, and tailor content to engaged subscribers. Don’t trigger throttles in the first place.
  • When dealing with throttling, consult your ESP and be patient bringing volumes back up to moderate levels again over an extended warmup period.
  • Occasional throttling is inevitable even for responsible senders. Accept limitations during peak traffic. Focus on temporary smoothing not permanent elimination.
  • Recipient experience is king. Ensure content quality and relevance supersedes any quotas or conversions. Throttling guides senders in the right direction.

With a nuanced understanding of causes, preservation of email access depends on collaboration between providers applying smart constraints and conscientious senders closely aligning messaging with subscriber needs. Avoiding disruption simply takes a little mindfulness and care.