MailSlurp

What MailSlurp does

MailSlurp, operated by Estonian private limited company Pettman OÜ, is a cloud-hosted SaaS platform that provides developers and quality assurance teams with programmable email accounts and real phone numbers for testing, automation, and deliverability monitoring. Built on AWS infrastructure and exposed via REST, IMAP/SMTP, and GraphQL interfaces, the platform supports test frameworks including Playwright, Cypress, and Selenium through native first-party plugins and SDKs in JavaScript, Python, C#, Java, PHP, and Ruby. The product portfolio spans email inboxes, phone number provisioning across 20+ global mobile networks, AI-based email parsing and structured data extraction, webhook-driven routing and automation, device rendering previews, deliverability and inbox placement tests, and domain monitoring for SPF, DKIM, and DMARC. Adjacent add-ons include team mailboxes, email auto-reply, audit and load testing, and an Enterprise module with SAML+SSO, role-based access controls, and isolated environments. The company is SOC 2 Type I compliant, GDPR- and CCPA-aligned, and hosted on ISO 27001-certified AWS facilities.

MailSlurp generates revenue through a freemium SaaS subscription model with monthly and annual tiers priced by API calls, inbox count, and feature access; recurring line rental plus usage-based SMS billing for provisioned phone numbers; and enterprise contracts negotiated through a dedicated sales team. Go-to-market is API-first and product-led, combining self-serve sign-up at app.mailslurp.com with distribution via AWS, Azure, Google Cloud, and GitHub Marketplaces. The company targets three primary customer segments — developers and QA teams using it for OTP/MFA and CI/CD automation, marketing teams using it for pre-send campaign QA, and enterprise teams using it for compliance-controlled messaging infrastructure. Named customers include Broadcom, Avast, Panasonic, Trivago, Wolt, and Scraper.

The company is privately held and bootstrapped, with a reported headcount of 1-10 employees, no disclosed external funding, and revenue figures that are not publicly disclosed. According to platform disclosures, MailSlurp has processed over 500 million emails across more than 10 years of operation and is led by CTO Jack Mahoney.

Name

MailSlurp

Legal name

Pettman OÜ

Website

https://mailslurp.com

Company type

Private

Founded year

2015

Operating status

Operating

Headcount range

1–10 employees

Short description

MailSlurp is a developer-focused SaaS platform that provides programmable email inboxes and phone numbers for software testing, automation, and deliverability monitoring, serving QA teams, developers, marketing teams, and regulated enterprises via APIs, SDKs, and cloud marketplace distribution.

Ownership category

akta.pro rank

Product category

Email & SMS Testing APIs (Developer Tools)

NAICS

Computing Infrastructure Providers, Data Processing, Web Hosting, and Related Services (518), Computing Infrastructure Providers, Data Processing, Web Hosting, and Related Services (5182)

SIC

Services-Prepackaged Software (7372), Services-Computer Programming, Data Processing, Etc. (7370)

akta.pro industry

PRIMARYBPAFAKAB

Email Marketing Services (Campaigns, Deliverability, Lifecycle)

Business & Public Services/Marketing, Advertising & PR Services/Direct Marketing & Lead Generation (Email, Telemarketing, Demand Gen)

SECONDARYHDADAKAC

Email Authentication & Domain Protection (DMARC/SPF/DKIM)

Hardware, Technology & Telecom/Cybersecurity/Email & Collaboration Security

Keywords

• Email testing API
• SMS testing API
• Virtual inboxes
• Email automation
• Deliverability monitoring

Headquarters

HQ city

Tallinn

HQ country

Estonia

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Software

Cost components

Personnel, Technology or R&D, Infrastructure, Marketing or Sales, Operations

Revenue model

1. SaaS Subscription Plans: Monthly or annual subscription tiers based on usage limits including API calls, inbox count, and feature access. Free tier available for initial testing.
2. Phone Number Provisioning: Real phone numbers billed monthly as line rental plus associated SMS usage plans for inbound/outbound messaging.
3. SMS Usage: Usage-based billing for SMS messages sent and received through provisioned phone numbers.

Pricing tiers

Go-to-market motion2 records

Distribution channels3 records

Marketing channels5 records

Core offering

MailSlurp provides a developer-facing SaaS platform that exposes APIs and SDKs for creating disposable virtual email inboxes and SMS numbers on demand. The platform is used to programmatically send, receive, and assert on email and SMS messages for end-to-end testing, workflow automation, and ongoing deliverability monitoring by engineering and QA teams.

Product overview

MailSlurp is an all-in-one messaging platform for developers and QA teams, offering programmable email accounts and phone numbers for testing, automation, and deliverability monitoring. The platform provides a unified portfolio of products organized across Build, Test, and Monitor categories. Core offerings include Email Inboxes and Phone Numbers for provisioning real messaging endpoints; AI Email Parsing for transforming inbound content into structured data; and Email Automation Routing for webhook-based workflow automation. Testing capabilities span Email Integration Testing with Playwright/Cypress/Selenium plugins, Device Previews for rendering validation, Email Load Testing, and Email Audit tools. Monitor products include Inbox Placement/Deliverability Tests, Email Compatibility Tester, Domain Monitor (SPF/DKIM/DMARC tracking), and Campaign Probe for content drift detection. Enterprise features add SAML+SSO, role-based access controls, and isolated team environments. The platform exposes REST, IMAP/SMTP, and GraphQL APIs with native SDKs in JavaScript, Python, C#, Java, PHP, and Ruby.

Differentiator

Problem solved

Functional benefit

Products and services

• Email & SMS Testing API REST API and SDKs that let developers programmatically create disposable email inboxes and SMS numbers, send and receive messages, and assert on message content for end-to-end testing and CI/CD workflows.
• Virtual Inboxes On-demand, disposable email addresses created via API for use as test endpoints in software testing, QA, and automation scenarios, without consuming real production mailboxes.
• Virtual SMS Numbers Programmable phone numbers exposed through the API for sending and receiving SMS messages during testing and verification of SMS-based application flows.
• Deliverability Monitoring Service for monitoring and validating that transactional emails reach the inbox, intended for teams that want to assert ongoing delivery health in production-adjacent environments.

Quantifiable outcome

• Reduced CI flakiness in account verification tests
• +2 more outcomes

Named customers5 records

Segments3 records

Ideal customer profiles1 record

Technology focussed Yes

API detail

Has API

Yes

API docs

API detail

Core technology

AI maturity

App detail

Integration5 records

AI capability5 records

Feature7 records

Scale indicators4 records

Recent moves6 records

Expansion highlights6 records

Broad incumbents

• Twilio: Twilio is a large communications platform offering email (SendGrid), SMS, and voice APIs. While not specialized in disposable inboxes, Twilio can bundle email testing-style functionality into its broader messaging suite, posing a competitive threat to MailSlurp.
• Mailgun: Mailgun is a developer-focused email API service for sending, receiving, and tracking transactional emails. MailSlurp explicitly positions itself alongside Mailgun in its messaging workflow framework, making Mailgun a comparable email API peer.
• SendGrid (Twilio): SendGrid is a leading transactional and marketing email API platform, now part of Twilio. It overlaps with MailSlurp on the email infrastructure and deliverability side, and is a frequent comparison point for engineering teams evaluating messaging tooling.
• MessageBird (now Bird): MessageBird is a multi-channel communications platform offering email, SMS, and WhatsApp APIs. It is comparable to MailSlurp in providing programmable messaging infrastructure for developers, though at much greater scale and across more channels.
• Postmark: Postmark is a transactional email delivery service known for reliability and fast delivery. It overlaps with MailSlurp on the email infrastructure side, particularly for teams building notification and authentication flows.

Emerging players

• MailerCheck: MailerCheck is an email deliverability and verification platform offering inbox placement testing, spam checks, and list verification. It is a niche player in the deliverability monitoring space where MailSlurp also competes.

Direct peers

• Litmus: Litmus is an email testing and analytics platform focused on pre-send rendering, deliverability, and link/asset validation. It competes directly with MailSlurp's device previews, email audit, and inbox placement products for marketing QA teams.
• Mailosaur: Mailosaur provides disposable email inboxes and phone numbers for end-to-end testing, with native integrations into test frameworks. It is a head-to-head competitor targeting the same developer QA and OTP testing use cases as MailSlurp.
• Mailtrap: Mailtrap is a developer-focused email testing platform that provides virtual inboxes for capturing test emails, with email API and email delivery products. It is the closest direct competitor to MailSlurp in the email/SMS testing category for developers and QA teams.
• Email on Acid: Email on Acid offers email rendering previews, spam testing, and deliverability checks. It is a direct competitor in the pre-send campaign QA and inbox placement category that MailSlurp also addresses.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

• Xx.com/MailSlurp
• GitHubgithub.com/mailslurp
• YouTubeyoutube.com/@mailslurp
• Facebookfacebook.com/people/MailSlurp/100093660243614
• LinkedInlinkedin.com/company/mailslurpdev
• Instagraminstagram.com/mailslurp

Compliance4 records

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about MailSlurp