EmailSuccess vs Plunk
EmailSuccess
emailsuccess.com
Plunk
useplunk.comSide by side
| Figure | EmailSuccess | Plunk |
|---|---|---|
| Price from | €333.33/mo | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | Yes |
| Windows | Yes | — |
| macOS | Yes | — |
| API | Yes | Yes |
| Self-hosted | Yes | Yes |
| Plans published | 4 | 4 |
| Spec score · Transactional Email Software | 9.4 (#1) | 7.8 (#31) |
| Spec score · Transactional email services | 9.1 (#4) | 8.1 (#23) |
| Free plan | Yes | Yes |
| Integrations | Listed technology integrations include Splunk, Elastic, Kafka, Pravega, HerdDB, Rspamd, Ongage, BlackBox and MySQL. | Plunk offers a REST API, SDKs including Node.js and Python, SMTP support, webhooks, and an MCP server that works with MCP clients such as Claude Code, Claude Desktop, and Cursor. |
| Product | EmailSuccess is an on-premises high-performance mail transfer agent for enterprise email gateways and high-volume SMTP servers. | Plunk is an open-source email platform for transactional email, marketing campaigns, and automated workflows against one contact list. |
| Support | The Free plan lists community forum support, while Standard and Enterprise list individual support. | The maker invites customer feedback and lists a Discord community on its site. |
Plans
In their own words
EmailSuccess
EmailSuccess is an on-premises mail transfer agent for enterprise email gateways and high-volume SMTP servers. It manages outbound delivery, sending reputation, and changing authentication requirements. Its deliverability engine analyzes ISP responses and adjusts delivery settings in real time. Flexible queues, multiple IP pools, and connection pooling support high-volume sending and traffic prioritization. Authentication features include DKIM signing, DMARC compliance, and SPF and SenderID monitoring; TLS delivery encryption can be governed by configurable rules. The product classifies and reports bounces and feedback loops, and can forward ISP spam complaints to another system. Sending and message analysis are supported through SMTP, input scripting and filtering, and REST and SOAP APIs. Management tools include VirtualMTA traffic segmentation, an SSH console, and a web interface for monitoring and message history. The Free plan costs nothing, billed annually, and lists 100,000 emails per day and two active IPs.