🚀 High-volume sending in WordPress, what mailer are you using (API)? SMTP is way too slow for me.

I use Amazon SES and Iam really happy with it.
+40.000 emails goes really fast (it costs only 4$) and I had never deliverability issues (gmail, yahoo, web, gmx, icloud, etc.) without to have a dedicated IP, its just important you have everything set correctly like SPF, DKIM, DMARC etc. and you dont spam or have spam content inside of your emails. About SES suppression list, you can disable it and let manage FluentCRM for it with Amazon SNS.

Today, we are sending almost 100K BFCM emails with FluentCRM + Amazon SES.

Does FluentSMTP use API sending with providers like Amazon SES, ElasticEmail, or SMTP2Go? Or is there some other better way to setup API sending from FluentCRM please? I'm about to embark on this setup and want to get it right for my wife's business. Thanks 😃❤️🙏

Hello everyone,

I’ve been following this thread closely, and honestly, I’m tired of seeing the same standard responses blaming SMTP providers or Cron configurations. I spent days "fighting" with FluentCRM support over this exact issue, and I need to expose what’s really happening to save you all some time.

I run a "beast" of a dedicated server (128GB RAM, 16 CPU Cores, NVMe, 30 public IPs) and use Elastic Email via FluentSMTP. Theoretically, I should be flying. In practice? My sending was choked at ~200 emails per minute.

For a long time, support kept telling me to increase PHP max_execution_time, check the server Cron, or blame SMTP latency. Total BS.

The truth that support hides (until you back them into a corner, like I did) is that FluentCRM has HARDCODED LIMITERS.

The issue isn't the SMTP protocol or API. The issue is that the plugin was designed to cap the amount of data it fetches from the database at a time—probably to protect cheap shared hosting—but this kills anyone with professional infrastructure who needs to scale.

After I audited the code myself and proved it to them, support finally admitted it and gave me the list of files where these "handbrakes" are hidden.

If you want real speed (above 10k/hour), forget about switching SMTPs for a moment. The bottleneck is HERE, inside the plugin folder:

1. Slow Automations:

In /wp-content/plugins/fluent-crm/app/Services/Funnel/FunnelProcessor.php, there is a line with ->limit(200). The plugin only processes 200 contacts per automation cycle, no matter if your server can handle 10,000.

I made this change:

$jobs = FunnelSubscriber::whereIn('status', $statuses)
->whereHas('funnel', function ($q) {
return $q->where('status', 'published');
})
->where('next_execution_time', '<=', current_time('mysql'))
->whereNotNull('next_execution_time')
->orderBy('next_execution_time', 'ASC')
->limit(6000)// Increased to process 6000 records at a time
->get();

1. Bulk Actions:

In /wp-content/plugins/fluent-crm/app/Http/Controllers/SubscriberController.php, there is a ->limit(400). Trying to tag 50k people? Sit down and wait, because it’s going 400 by 400.

I made this change:

$subscribersModel = $subscribersModel->select(['id'])
->limit(3000) // Increased the batch size
->where('id', '>', $lastId)
->get();

1. Email Sequences:

In /wp-content/plugins/fluentcampaign-pro/app/Hooks/Handlers/EmailScheduleHandler.php, the query for next sends is done via SequenceTracker::ofNextTrackers()->limit(XXX). The default limit is extremely low. I had to force change the code to ->limit(1000), otherwise it spoon-feeds the queue and the sending never finishes.

I made this change:

$processTrackers = SequenceTracker::ofNextTrackers()->limit(1000)->get();

What makes me angry:

They know this. In my ticket, after I sent a video proving my hardware was idling while the plugin was "sleeping", the developer (Masiur) finally said: "You can adjust the values in these files to increase volume, but we don't support that."

In other words, they sell a marketing automation tool but hide the fact that it comes "crippled" out of the box. I had to manually edit the plugin core (which is terrible for future updates) just to utilize my server’s power.

So, answering the OP: Amazon SES is great, use the API. But if you don't change these internal limits in the FluentCRM code, you could hire a NASA server and the sending will still be slow.

Honestly, I don't know if I caught all the throttles, as the code operates like a "black box" that the team refuses to document for the community. I still notice slowness in other areas, and I know the standard answer will be to blame my server, but tests prove the software is the brake.

You need to IMMEDIATELY document all these hidden limitations (hard limits) scattered throughout the code—whether in flows, timeouts, or processing batches (contacts processed per minute). Selling an "unlimited" tool that comes throttled out of the box is shameful.

Be warned: stop blaming the SMTP before looking at how the plugin queries the database or hands off emails to the SMTP.

As I was writing this reply, my wife asked me why I was banging on the keyboard so hard.

I hope Shahjahan Jewel reads this.

Best regards.