Best Email Marketing Tools for Startups in 2025

The percentage of recipients of your emails who flagged them as spam is known as your spam complaint rate. For instance, your spam rate is 0.1% (5/5,000) if you send 5,000 messages and 5 of those recipients designate them as spam.

Anything less than 0.1%, or one complaint for every 1,000 delivered messages, is the industry benchmark for acceptable spam complaint rates. Above this threshold, anything is regarded as high. Leading inbox providers like Gmail have established this as the industry standard.

An email sender's reputation, deliverability, and brand credibility can all be adversely impacted by a high spam complaint rate. More than one complaint per 1,000 emails is regarded as high as the industry guideline for a spam complaint rate is 0.1% or below.

Deliverability: Emails sent to Gmail, Yahoo, AOL, and other email providers may bounce or land in the spam folder.

Reputation: ISPs may reject emails from senders with a bad reputation.

Credibility of brand: Recipients may come to distrust and be disloyal to the sender's company.

Some of the best practices are as follows:

• Find the right sender
• Make the process unsubscribing clean and simple
• Use segmentation and personalization
• Remove the inactive users.

Mailbird or Thunderbird are some of the best desktop-based email marketing software.