Your deliverability is our priority.
SendState protects sender reputation at every layer: mailbox, domain, campaign, and list. Automatic throttling, pause rules, and a risk-scoring Guardian keep you off blocklists and in the inbox.
Whether you send from one mailbox or dozens, cold email only works when it lands. We monitor bounce rate, complaint rate, domain reputation, and list quality in real time. When something crosses a threshold, we slow or stop the send and log the reason. You stay in control and in the inbox.
Protection layers
Major blacklists monitored
Audit log for every event
Why deliverability protection matters
Cold email only works when it lands in the inbox. One bad run can tank a domain: high bounce rates, complaints, or blocklist listings lead to filters and blacklists. Recovery is slow and expensive. Once a domain is burned, you often have to switch infrastructure, warm up again, or wait weeks for reputation to recover.
Most sending tools focus on volume and rotation. They tell you how many emails went out, not how close you are to the edge. SendState applies protection at the mailbox, domain, campaign, and prospect level. When bounce rate spikes, complaint rate rises, or a domain hits a blocklist, the system throttles or pauses before you burn reputation. Every decision is written to an audit log with a reason code, so you know exactly why a send was slowed or stopped and what to fix.
The goal is simple: keep you off blocklists and in the inbox. Protection runs on every send, for every plan. No extra add-on, no separate deliverability product. It is built into the platform.
Without protection
- Bounce spikes burn the domain before you notice
- Complaints and blocklists kill inbox placement
- No audit trail when something goes wrong
With SendState
- Auto-throttle and pause on bounce and complaint thresholds
- Blacklist checks and domain reputation before send
- Full deliverability event log with reason codes
What happens when something goes wrong
Imagine you launch a campaign and the first 50 sends produce an unusually high number of bounces. Without protection, you might not notice until hundreds more have gone out. By then, the receiving providers (Gmail, Outlook, etc.) have already started to treat your domain more strictly. Inbox placement drops. Recovery takes time.
With SendState, bounce rate is tracked per mailbox and per campaign in real time. When the rate crosses a warning or critical threshold, the system automatically throttles or pauses sending for that mailbox or campaign. You get a deliverability event in the log with a reason code (e.g. bounce velocity spike, complaint rate exceeded). You can open the Deliverability dashboard, see which rule fired, clean the list or fix the issue, and resume when you are ready. The domain is protected because the system reacted before the damage spread.
The same logic applies to complaints, blocklist listings, and domain reputation. When any monitored signal goes bad, the system slows or stops the send and logs it. You stay in control and in the inbox.
Who it's for
Built for teams that care about inbox placement
Deliverability protection in SendState is built for anyone who sends cold email at scale and cannot afford to burn a domain. That includes B2B agencies running campaigns for multiple clients, SDR teams with shared or dedicated mailboxes, and founders or solopreneurs who send from one or a few domains. If you rely on cold email for pipeline, you need to know that bounces, complaints, and blocklists are monitored and that the system will pause or throttle before reputation is damaged.
Agencies
Multiple clients, multiple domains. Protection runs per mailbox and per domain so one bad campaign does not affect others. Audit log and dashboard show exactly what happened and where.
SDR and sales teams
Shared or dedicated mailboxes, high volume. Bounce and complaint thresholds plus recipient-domain limits keep sending patterns safe. Auto-pause and throttling protect the team's primary domains.
Founders and solopreneurs
One or a few domains, no room for error. Health scoring, warmup-aware limits, and the Deliverability Guardian reduce the risk of a single bad list or bad day taking down your main sending domain.
How it works
Protection at every layer, before and during send
Mailbox health and limits
Each mailbox has a health score based on bounce rate, reply rate, and daily usage. Daily sending limits respect warmup: newer or lower-reputation accounts get lower caps so you don't blast from day one. When health drops or the daily limit is hit, sending is paused or throttled automatically. Complaint rate is factored in; if recipients start marking emails as spam, the mailbox is slowed or paused before providers penalize the domain.
The result: you send within safe bounds per mailbox. No guessing. The system enforces the cap and the health rules so one overloaded mailbox does not burn your setup.
Health score, daily limits, warmup schedule, complaint rate
Domain reputation and blacklists
Sending domains are scored from bounce rate, reply rate, and complaints. If a domain exceeds bounce thresholds or its reputation score drops too low, the campaign is throttled or paused so you don't keep sending from a damaged domain. Major blocklists (Spamhaus, Spamcop, Barracuda, SORBS) are checked on a schedule; if a domain is listed, sending from that domain is paused until the listing is resolved. You see the status in the dashboard.
This layer protects the asset that is hardest to replace: your sending domain. Once a domain is on a blocklist or has poor reputation, recovery is slow. Checking before and during send reduces the chance you discover the problem too late.
Domain score, bounce threshold, blacklist check, pause and throttle rules
Bounce and complaint monitoring
Bounce rate is tracked per mailbox and per campaign in real time. When it crosses a warning or critical threshold, the system throttles or pauses so you don't keep hitting bad addresses. Complaint rate is monitored the same way: above a set level, the mailbox is paused before providers start filtering or blocking. Hard bounces can trigger automatic prospect removal so the same bad address does not count against you twice. Bounce velocity (a sudden spike in a short window) also triggers throttling, because a spike often means a bad list or a configuration issue.
These signals are among the fastest ways to burn a domain. Catching them early and pausing or throttling keeps your reputation intact and gives you time to fix the list or the content.
Bounce velocity spike, complaint rate, auto-pause, prospect removal
Recipient limits, timing, and risk scoring
To avoid overloading one provider, SendState limits how many emails you send to the same recipient domain (e.g. Gmail, Outlook) per mailbox per day. Sending too much to one provider in a short window can trigger filters. Send timing is randomized so patterns look human, not robotic. List quality is checked early: for example, if the first 50 sends produce a high bounce rate, the system can pause so you don't blast the rest of a bad list. Content can be scored for spam signals so obviously risky copy is flagged or blocked. A Deliverability Guardian combines domain reputation, mailbox health, list quality, content signals, and historical engagement into one risk score; when the score is too high, the system throttles or blocks campaign launch to protect your reputation.
Together, these controls keep sending volume and pattern within safe bounds. You get the benefit of automation without the risk of looking like a bot or burning a domain in one run.
Per-domain recipient limits, human-like delay, list quality, content spam score, AI Guardian
What we protect
A short checklist of what runs automatically. Every item below is enforced by the platform so you don't have to remember to turn it on.
- Mailbox health scoring, bounce thresholds, and warmup-aware daily limits
- Domain reputation, recipient-domain limits (e.g. Gmail, Outlook), and blacklist checks
- Engagement and complaint monitoring with auto-pause
- AI Deliverability Guardian and full protection audit log
- Bounce velocity spike detection and throttling
- List quality detection (e.g. first 50 sends bounce rate triggers pause)
- Content spam scoring and optional block
- Human-like send timing and daily send curve
Deliverability protection works alongside SendState's Research Agent: better research leads to more relevant emails and fewer complaints. Protection keeps those emails in the inbox.
How SendState deliverability is different
Many cold email tools focus on volume and warmup: they rotate mailboxes, cap daily sends, and tell you how many emails went out. Few combine that with domain and mailbox health scoring, per-recipient domain limits (so you don't overload Gmail or Outlook in one burst), bounce and complaint monitoring with automatic pause, list quality checks, content spam scoring, and a single risk-scoring Guardian that can block campaign launch when the combined risk is too high.
SendState does. Every protection event is logged with a reason code. You get a full audit trail in the Deliverability dashboard so you know exactly why a send was slowed or stopped and what to fix. No black box. Protection is included in every plan and runs on every send. If you care about inbox placement and long-term sender reputation, this is how we're built to support it.
Common questions
SendState applies protection at multiple layers: mailbox health scoring and daily limits, domain reputation and blacklist checks, bounce and complaint monitoring with automatic pause, per-recipient domain send limits (e.g. Gmail, Outlook), engagement-based throttling, list quality detection, and an AI Deliverability Guardian that scores risk before sending. Every protection event is logged for audit.
When bounce rate exceeds configured thresholds, SendState automatically throttles or pauses sending for the affected mailbox or campaign. Hard bounces can trigger prospect removal. Bounce velocity spikes (sudden spikes in a short window) also trigger throttling so you avoid burning a domain before you notice.
Yes. SendState can check major DNS blocklists (e.g. Spamhaus, Spamcop, Barracuda, SORBS) for your sending domains. If a domain is listed, sending from that domain is paused until the listing is resolved.
The AI Deliverability Guardian is a risk-scoring layer that combines domain reputation, mailbox health, list quality, content spam signals, and historical engagement into a single risk score. When the score is too high, the system throttles or blocks campaign launch to protect your reputation.
Yes. Every throttle, pause, and block is logged in the deliverability events log with reason codes. You can review these in the Deliverability dashboard to understand exactly which rule fired (e.g. bounce spike, complaint rate, domain reputation, recipient domain limit).
SendState respects warmup by applying daily sending limits that scale with mailbox age and health. Newer or lower-reputation mailboxes get lower caps. The system does not replace a dedicated warmup tool; it protects the mailbox once you start sending by throttling when limits or health thresholds are hit.
Thresholds are configurable where applicable. You can set warning and critical levels for bounce rate and complaint rate. When a threshold is crossed, the system throttles or pauses according to your settings so you control how aggressive protection is.
SendState can check major DNS blocklists including Spamhaus, Spamcop, Barracuda, and SORBS. If your sending domain appears on any monitored list, sending from that domain is paused until the listing is removed. You see the status in the Deliverability dashboard.
Yes. Deliverability protection runs on every send for every plan. Throttling, pause rules, blacklist checks, and the Deliverability Guardian are part of the platform. The Deliverability dashboard and audit log are available so you can see why sends were slowed or stopped.
Many tools focus on volume and warmup only. SendState adds domain and mailbox health scoring, per-recipient domain limits (so you don't overload Gmail or Outlook), bounce and complaint monitoring with auto-pause, list quality checks, content spam scoring, and a single risk-scoring Guardian that can block campaign launch. Every protection event is logged with a reason code so you have a full audit trail.
Your deliverability is our priority.
Protection runs on every send. Throttles and pauses are logged. You stay in control and in the inbox. See Research Agent for how we personalize every email, and pricing for plans and limits.
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