Instantly.ai has become the default cold email platform for B2B outbound teams running serious volume. Beyond sending infrastructure, it now includes a built-in lead database of 450M+ verified contacts on higher plans, an AI Reply Agent, and a native CRM. Its warmup network, multi-mailbox rotation, and Clay integration make it the most practical choice for scaling from 100 to 5,000 daily sends without burning domains. But how you configure it matters as much as which plan you are on. This guide covers the full setup from domain infrastructure through to live campaign launch — the right way, not the fast way.
Before You Open Instantly: Domain Infrastructure First
The biggest setup mistake teams make is connecting mailboxes to Instantly before the underlying domain infrastructure is correct. Fix the foundation first:
- Never send cold outreach from your primary domain (yourcompany.com). Use secondary sending domains
- Register 3–5 secondary domains per campaign (e.g., trycompany.com, getcompany.com, companyhq.com)
- Configure SPF, DKIM, and DMARC records on every domain before connecting to Instantly
- Create 2 mailboxes per domain (this is the optimal ratio for warmup and volume distribution)
For complete DNS record setup instructions, see our guide on setting up cold email sending domains. For SPF, DKIM, and DMARC configuration specifics, see our email deliverability setup guide.
Step 1: Create Your Instantly Account and Add Email Accounts
Sign up at instantly.ai and select a plan. The Growth plan ($37/month) is the right entry point for most teams — it supports unlimited email accounts and up to 1,000 active contacts in sequences at a time.
To add email accounts:
- Go to Email Accounts → Add Account
- Select your provider: Google Workspace, Microsoft 365, or Custom IMAP/SMTP
- For Google: authenticate via OAuth. For Microsoft: use OAuth or App Password. For custom providers: enter IMAP and SMTP server details manually
- Repeat for all mailboxes across all sending domains
- Verify each account shows a green “Connected” status before moving on
Step 2: Enable and Configure Warmup
Email warmup is non-negotiable for new domains and mailboxes. Instantly’s warmup network has grown to 4.2 million real mailboxes — one of the largest deliverability pools available — exchanging and engaging with warmup emails to build domain reputation.
For each connected email account:
- Navigate to the account settings and toggle Warmup On
- Set initial warmup volume: 3–5 emails/day for the first week
- Enable Smart Warmup to let Instantly auto-increase volume based on reputation signals
- Set the warmup tag or category to match your niche for more relevant warmup content
Run warmup for a minimum of 4–6 weeks before starting live campaign sends. Do not rush this — warm domains that have been building reputation for 6 weeks outperform freshly connected domains that have been warmed for 2 weeks, and the difference shows up immediately in inbox placement rates. See our full guide on email warmup for new domains for the full methodology.
Step 3: Create Your First Campaign
After warmup, go to Campaigns → New Campaign and work through the setup:
Campaign Name and Schedule
Name campaigns descriptively: [ICP segment] — [offer/angle] — [date]. This matters when you are running 5+ concurrent campaigns.
Set the campaign schedule to your target audience’s business hours. A standard configuration: Monday–Friday, 8:00 AM–5:00 PM in the prospect’s local time zone. Avoid sending on weekends unless your data shows your audience is active then.
Sending Accounts
Assign all warmed sending accounts to the campaign. Instantly distributes sends across all assigned accounts automatically. With 10 accounts, each account sends fewer emails per day — protecting individual domain reputation while increasing total campaign volume.
Daily Sending Limits
Set conservative per-account limits during the first 2 weeks of a live campaign:
- Week 1–2: 20–25 emails per account per day
- Week 3–4: 30–40 per account per day (if metrics look healthy)
- Week 5+: 40–50 per account per day (maximum recommended for cold email)
Never exceed 50 emails per mailbox per day for cold outreach. Note that Instantly’s Growth plan has a hard cap of 5,000 emails/month — upgrade to Hypergrowth ($97/mo) before hitting this ceiling to avoid campaign interruption. — above this threshold, you are consistently risking reputation damage regardless of how well-warmed the domain is.
Step 4: Build Your Email Sequence
In the campaign builder, add your email steps. A standard 4-step cold email sequence in Instantly:
| Step | Delay | Length | Focus |
|---|---|---|---|
| Email 1 | Immediate | 60–90 words | Cold intro — problem + relevance signal + soft CTA |
| Email 2 | Day 3 | 40–60 words | Follow-up — different angle, no apology |
| Email 3 | Day 8 | 50–80 words | Social proof or result reference |
| Email 4 | Day 16 | 30–50 words | Breakup email — close the loop professionally |
Add personalisation variables using Instantly’s merge tag syntax: {{first_name}}, {{company}}, and any custom fields you map during contact upload (e.g., {{opening_line}} for Clay-generated personalisation).
Step 5: Upload Your Contact List
Navigate to Contacts → Upload and import your CSV or push directly from Clay via the native integration.
Before uploading, verify your list has been email-verified (ZeroBounce or NeverBounce output). In Instantly settings, enable:
- Skip contacts already in sequences: Prevents duplicate sends to the same contact
- Auto-remove bounces: Instantly removes hard bounces automatically — confirm this is active
- Stop on reply: Pauses the sequence for any contact who replies — always keep this enabled
Step 6: Configure the Unified Inbox
Instantly’s unified inbox consolidates replies from all connected sending accounts in one place. Configure it before your campaign goes live:
- Set up labels: Interested, Not Now, Not a Fit, Out of Office, Auto-Reply
- Enable auto-classification to let Instantly’s AI categorise replies
- Connect to your CRM (HubSpot or Salesforce) to push Interested replies as contacts or deals automatically. Enable Instantly’s AI Reply Agent to respond to common inbound messages in under 5 minutes — keeping momentum while your team sleeps.
- Assign an inbox manager to review and respond within 30 minutes of an Interested reply — speed matters here
Step 7: Monitor Key Metrics Weekly
Once live, track these in Instantly’s analytics dashboard weekly:
| Metric | Healthy Range | Action if Below |
|---|---|---|
| Open rate | 40–60% | Test subject lines or check deliverability |
| Reply rate | 3–8% | Rewrite Email 1 body or tighten targeting |
| Bounce rate | Below 3% | Re-verify list immediately |
| Unsubscribe rate | Below 0.5% | Check offer fit and targeting |
| Spam complaint rate | Below 0.1% | Pause campaign, investigate immediately |
Conclusion
Instantly.ai is one of the most capable cold email platforms available for B2B outbound, but the setup determines your results more than the platform itself. Domain infrastructure, proper warmup duration, conservative initial sending limits, and clean verified contact lists are the four factors that separate campaigns that hit 5%+ reply rates from ones that burn domains in the first two weeks. Get the foundation right and Instantly will perform. Rush the setup and no deliverability feature will save you.
Frequently Asked Questions
How many email accounts do I need in Instantly?
A minimum of 3 warmed accounts for any live campaign. For campaigns targeting 300+ daily sends, 6–10 accounts is the recommended configuration to keep per-mailbox volume in the safe range.
How long does Instantly warmup take?
A minimum of 4 weeks before live campaign sends. 6 weeks is better. The first 2 weeks build basic reputation; weeks 3–6 consolidate it. Rushing warmup is the most common cause of early deliverability problems.
Can I send from my primary domain in Instantly?
Technically yes, but never recommended for cold outreach. Use secondary sending domains to protect your main domain’s email reputation for transactional and marketing emails.
Does Instantly work with Clay?
Yes. Instantly has a native Clay integration. You can push contacts with custom personalisation variables directly from a Clay table into an Instantly campaign without CSV export.
What is the best Instantly plan to start with?
The Growth plan ($37/month) is the right starting point for most teams. It supports unlimited email accounts, which is the most important feature for proper domain rotation, at an accessible price point.
Instantly.ai official documentation | Google Postmaster Tools — monitor your domain reputation | Validity Sender Score — check your sending reputation
