Email Sending — Business Overview
Last updated: February 2026
Feature Owners
| Role | Owners |
|---|---|
| Product manager | Kristijan Todorov |
| IT project manager | Martina Todorovska |
| Lead developer | Nikola Doncev |
| Stakeholders | Kristijan Todorov, Boban Ilievski |
Table of Contents
- What Is Email Sending?
- Why It Matters
- How It Works — The Big Picture
- Scheduling — Timing the Messages
- Sending via Postal
- Tracking — Opens and Clicks
- Response Handling
- Follow-Up Chasers
- What Users See
- Glossary
1. What Is Email Sending?
Email Sending is the engine that delivers Sopro's outreach messages to prospects. It handles everything from scheduling when emails go out, to actually sending them through a self-hosted mail server, to tracking what happens after delivery — did they open it? Did they click a link? Did they reply?
In Simple Terms
"Email Sending is like a postal service for digital outreach — it picks up your message, delivers it on schedule, and tells you whether the recipient opened the envelope."
2. Why It Matters
| Challenge | How Email Sending Helps |
|---|---|
| Sending thousands of personalised emails manually | Automated, queue-based delivery at scale |
| Knowing whether prospects engaged with messages | Real-time open and click tracking |
| Managing sender reputation to avoid spam folders | Self-hosted mail server with careful scheduling |
| Following up with unresponsive prospects | Automated chaser sequences |
| Handling bounces and complaints | Automatic detection and processing |
3. How It Works — The Big Picture
The Core Loop
- Schedule — The system determines which prospects to email and when
- Queue — Messages are placed in a processing queue for reliable delivery
- Send — Each message is sent through Sopro's self-hosted Postal mail server
- Track — Opens (via tracking pixel) and clicks (via rewritten URLs) are monitored
- Respond — Replies, bounces, and complaints are automatically processed
- Report — Campaign statistics are updated in real-time
4. Scheduling — Timing the Messages
Email scheduling is carefully controlled to protect sender reputation and ensure optimal delivery.
How Scheduling Works
Key Scheduling Concepts
| Concept | Description |
|---|---|
| Daily volume | Maximum emails sent per day per campaign (protects sender reputation) |
| Send window | Hours during which emails are delivered (typically business hours) |
| Staggering | Spreading sends evenly to avoid sudden bursts |
| Warm-up | Gradually increasing volume for new sender profiles |
5. Sending via Postal
Sopro operates its own mail server using Postal, a self-hosted open-source mail delivery platform. This gives full control over email delivery, tracking, and reputation.
Why Self-Hosted?
| Self-Hosted Advantage | vs. Third-Party Service |
|---|---|
| Full control over sending infrastructure | Limited control over shared infrastructure |
| Complete tracking data ownership | Tracking data shared with service provider |
| Custom configuration for Sopro's needs | Generic configuration options |
| No per-email cost from third parties | Pay-per-email pricing |
The Delivery Process
6. Tracking — Opens and Clicks
Open Tracking
When a recipient opens an email, a tiny invisible image (called a tracking pixel) is loaded from Sopro's server. This load event records:
- Who opened the email
- When they opened it
- Where they were (approximate location from IP)
- What device they used
Click Tracking
Links in emails are rewritten to pass through Sopro's tracking server before redirecting to the actual destination. This records:
- Which link was clicked
- When it was clicked
- How many times it was clicked
7. Response Handling
The system automatically processes different types of responses:
Response Types
| Response Type | What Happens |
|---|---|
| Reply | Forwarded to client, classified by AI (positive/negative/referral) |
| Hard Bounce | Email address removed from future campaigns |
| Soft Bounce | Retried later (temporary delivery failure) |
| Out of Office | Noted and follow-up may be rescheduled |
| Complaint | Prospect is suppressed from all future outreach |
8. Follow-Up Chasers
If a prospect doesn't respond to the initial email, the system can automatically send follow-up messages (called chasers).
Chaser Sequence
Key Rules
- Respect responses — If a prospect replies (even negatively), no more chasers
- Respect bounces — If the email bounced, no follow-up attempts
- Configurable timing — The gap between messages is adjustable per campaign
- Different content — Each chaser uses a different message to avoid appearing robotic
9. What Users See
Sodastream (Internal CRM)
| Feature | Description |
|---|---|
| Send Queue | View messages waiting to be delivered |
| Delivery Status | Track which emails have been sent, opened, clicked |
| Response Feed | See incoming replies with AI classification |
| Bounce Report | Monitor failed deliveries |
| Campaign Schedule | Configure daily volumes and send windows |
Data Admin
| Feature | Description |
|---|---|
| Campaign Statistics | Charts showing open rates, click rates, reply rates over time |
| Prospect Status | Per-prospect delivery and engagement status |
10. Glossary
| Term | Definition |
|---|---|
| Postal | Sopro's self-hosted open-source mail server used for delivering campaign emails. |
| Tracking Pixel | A tiny invisible image embedded in emails that records when the email is opened. |
| URL Rewriting | The process of replacing links in emails with tracked versions that record clicks. |
| Tracking Domain | A custom domain (e.g., track.client-outreach.com) used for tracking links and pixels. |
| Bounce | A failed email delivery — either permanent (hard bounce) or temporary (soft bounce). |
| Chaser | A follow-up email sent when a prospect doesn't respond to the initial message. |
| Send Window | The hours of the day during which emails are delivered (typically business hours). |
| Warm-up | Gradually increasing the number of emails sent from a new sender profile to build reputation. |
| Sender Reputation | A score assigned to an email sender by email providers — higher reputation means better deliverability. |
| Suppression | Permanently preventing a prospect from receiving any future emails (typically after a complaint). |
| Queue | A processing pipeline where outgoing emails wait to be delivered in order. |
| AI Classification | Automated categorization of replies as positive, negative, referral, or query using artificial intelligence. |