Alternatives

Products that do what InboxSignal does

Stop guessing why your cold emails get ignored

1. 1
   Email Warm-Up Tool by Reply▲325

   Make sure your emails land in the inbox, not spam

   2021

2. 2
   Mailwarm 2.0▲683

   The email warmup tool, upgraded for deliverability.

   Jun 2026 · mailwarm.com

3. 3
   Cold Email Analyzer by Mailshake▲222

   Real-time analysis of email subject lines and copy

   2018

4. 4
   Quicklines▲138

   Cold email personalized AI icebreakers to get more responses

   2022

5. 5
   Silent Inbox for Gmail▲251

   Receive unimportant emails and newsletters on your schedule

   2020

6. 6
   Warmbox▲387

   Warm-up your inbox and never land in spam

   2021

7. 7
   Warmup Inbox▲204

   Free email spam checker & inbox placement tester

   2023

8. 8
   NudgeForMe▲286

   AI follow-up agent for missed email opportunities

   Aug 2026 · nudgeforme.com

9. 9
   Warmup Your Email▲153

   Always land in Inbox by establishing sender reputation

   2021

10. 10
    Cold Email Rating by Datananas▲215

    Write your cold email, and get advices on how to improve it.

    2017

11. 11
    Email Warmup by Boxward▲144

    Get more cold emails opened, get more sales, automatically

    2022

12. 12
    InboxFee▲79

    Make strangers pay for their cold emails

    2020

13. 13
    Proxelion▲2

    AI cold emails that actually get replies

    May 2026 · proxelion.com

14. 14
    Ultimate Cold Email Research▲88

    The #1 guide to doing research before sending cold emails

    2018

15. 15
    Make senders work to get into your inbox▲44

    Hi HN :) really excited to share this with you. The one thing AI reliably does is generate noise. Half the tools I see launch are just machines for producing more noise across more channels. And people are starting to see this in the form of emails in their inboxes as spam filters are struggling. There used to be a useful signal in email: the effort a sender put into customizing a message was a rough proxy for how relevant it actually was. AI killed that. Now it's customized slop with the appearance of effort with none of the cost. It is painful that the open internet / open channels…

    Jul 2026 · captchainbox.com

16. 16
    Inbox Ignite▲85

    Prevent your emails from going into spam

    2019

17. 17
    Reply.id▲81

    Supercharge your inbox with our AI Gmail filter

    2018

18. 18
    Autoklose 2.0▲124

    Cold email reimagined 💌

    2020

19. 19
    Avec▲112

    Tinder for Email to handle your inbox in seconds

    Apr 2026 · avec.ai

20. 20
    Sendlyio▲14

    Cold email that actually replies

    Jun 2026 · sendlyio.com

21. 21
    Cold Email Doctor▲2

    Score a cold email for spam, replies, and CAN-SPAM

    4d ago

22. 22
    Emareach AI▲3

    Stop Landing in Spam. Start Getting Replies.

    Apr 2026 · emareach.com

23. 23
    InboxQualify▲3

    Stop sending emails into the void

    2025

24. 24
    Sendable▲5

    Fix AI-sounding cold emails before you send them

    Dec 2025

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