An email service provider is a platform built to send email to many people on a business’s behalf, along with the tools around it: contact lists and segments, an email editor, automation, sign-up forms, reports and deliverability features. Businesses use an ESP instead of a normal mailbox because personal email services limit how many messages you can send and aren’t designed for unsubscribes, tracking or bulk sending.
Behind the scenes, an ESP manages sending infrastructure and reputation, handles bounces and complaints, adds unsubscribe headers, and spreads large sends over time so mailbox providers don’t throttle them. Many also send transactional email such as receipts and OTPs through an API. Some let you plug in your own sending service, like Amazon SES or an SMTP server, while still using the ESP’s editor and automation.
When choosing one, look beyond the editor. Check how pricing grows with contacts and emails, what deliverability tools exist, whether automation is visual and flexible, how it connects to your store or CRM, and whether support works in your time zone. Indian businesses often also care about pricing in rupees, GST invoices and payment by UPI or netbanking.
Switching ESPs carries a few risks. Your sending reputation partly depends on your domain, which moves with you, but a new platform may mean new IPs and DKIM keys, so plan a short warm-up. Export your suppression list and unsubscribes along with your contacts; forgetting them means mailing people who asked you to stop.
A Pune clothing label outgrows sending newsletters from its Gmail account after hitting daily limits during a sale. It moves to an ESP, imports 7,000 contacts with their consent sources, imports its unsubscribes as suppressions, authenticates its domain and warms up over two weeks.
MailNesto is an email service provider for campaigns, automations and transactional email, priced in rupees with GST invoices, and it also lets you connect your own sending service such as Amazon SES, SendGrid or any SMTP server.