Instantly vs Warmbox
Choosing between Instantly and Warmbox? Both are popular tools for email warmup, but they take different approaches. Instantly focuses on high-volume cold emailers and agencies who need unlimited sending accounts, while Warmbox is designed for teams that need dedicated, professional email warmup alongside their outreach tool. Warmbox is more affordable at $15/mo vs $30/mo. Below, we compare them feature by feature to help you decide which is the better fit for your outreach stack.
Last updated: February 2026Instantly
High-volume cold email platform with unlimited accounts and built-in warmup network.
Warmbox
Dedicated email warmup tool with AI-driven inbox interactions and deliverability monitoring.
Feature-by-Feature Comparison
| Feature | Instantly | Warmbox |
|---|---|---|
| Starting Price | $30/mo | $15/mo |
| Free Plan | ||
| Free Trial | 14 days | 7 days |
| G2 Rating | 4.8 | 4.5 |
| Best For | High-volume cold emailers and agencies who need unlimited sending accounts | Teams that need dedicated, professional email warmup alongside their outreach tool |
| Year Founded | 2021 | 2021 |
| Features | ||
| Unlimited email accounts | ||
| Email warmup network | ||
| Unibox for reply management | ||
| A/B testing | ||
| Campaign analytics | ||
| Lead database add-on | ||
| API access | ||
| Account rotation | ||
| AI-driven warmup interactions | ||
| Multiple warmup strategies | ||
| Deliverability monitoring | ||
| Blacklist checking | ||
| Warmup analytics | ||
| DNS record checker | ||
| Auto warmup scheduling | ||
| Inbox placement testing | ||
| Pros | ||
| Key Advantages |
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| Cons | ||
| Limitations |
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Our Verdict: Instantly vs Warmbox
Instantly and Warmbox both have their strengths, but the best choice depends on your specific outreach needs.
Choose Instantly if you prioritize unlimited email accounts on all plans. It starts at $30/mo with a 4.8/5 G2 rating and works best for high-volume cold emailers and agencies who need unlimited sending accounts.
Choose Warmbox if you need focused and effective warmup solution. It starts at $15/mo with a 4.5/5 G2 rating and is designed for teams that need dedicated, professional email warmup alongside their outreach tool.
If neither is the right fit, we recommend FoxReach — it combines cold email automation, built-in warmup, AI replies, and deliverability monitoring in one platform, starting from a free plan.