What RSPAMD LTD does

Rspamd Ltd. is a privately-held, Cambridge UK-based software company that develops and maintains Rspamd, an open-source email security framework licensed under Apache 2.0. The core engine is written in C with an event-driven asynchronous architecture and Lua scripting framework, providing multi-layer email protection that combines reputation filtering, sender authentication (SPF, DKIM, DMARC, ARC), regex-based content analysis, Bayesian classification, neural networks, and fuzzy hashing. The platform integrates with major MTAs (Postfix, Exim, Sendmail) via the Milter protocol, supports ClamAV and commercial antivirus engines, and connects to Redis for statistics and caching and to ClickHouse/Elasticsearch for analytics. The 4.0.0 release in March 2026 introduced Protocol v3 (multipart scan protocol with JSON/msgpack), native FastText integration, native HTTPS support, and the HTTPCrypt encryption protocol using X25519 and XChaCha20-Poly1305.

The company's commercial offering consists of three premium tiers layered on the free open-source engine: Scale at £100+VAT/month for 5,000 mailboxes, Enterprise with custom pricing for 50,000+ mailboxes, and a fully managed Hosted tier. Premium features include access to a premium fuzzy hash database with longer retention, Neural/FastText models, priority support with SLA, the Rspamd Console operational dashboard with LLM-assisted rule authoring, custom development, and rsync DNS zones. The go-to-market is hybrid: a self-serve open-source distribution model via Docker, package repositories, and GitHub drives community adoption (reported 100,000+ installations since 2008, 2,500+ GitHub stars, 20+ active contributors), while direct sales handle Enterprise and Hosted contracts targeting large organizations, email service providers, and hosting providers processing millions of messages daily.

Rspamd has 1-10 employees, is founder-led by maintainer Vsevolod Stakhov, has no disclosed institutional funding, and operates as an independent UK private limited company. The company reports 100+ enterprise users, and its differentiation rests on 10-20x performance advantage over SpamAssassin (5-10 vs. 0.5-2 messages/second/core), 50-100MB memory footprint per worker, 1500 messages/second throughput demonstrated in production, and AI/LLM-powered detection capabilities including GPT plugin and Ollama integration for novel phishing detection.

Name

RSPAMD LTD

Legal name

Rspamd Ltd.

Website

https://rspamd.com/

Company type

Private

Founded year

2016

Operating status

Operating

Headcount range

1–10 employees

Short description

Rspamd Ltd. develops and maintains Rspamd, an open-source email security engine (Apache 2.0) providing spam, phishing, and malware filtering with Bayesian, neural, and LLM-based detection. It serves enterprises, ESPs, and hosting providers via three premium subscription tiers atop the free core.

Ownership category

akta.pro rank

Product category

Email Security Software

NAICS

Software Publishers (513210), Computing Infrastructure Providers, Data Processing, Web Hosting, and Related Services (5182)

SIC

Services-Prepackaged Software (7372)

akta.pro primary industry

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

Keywords

• Email security software
• Spam filtering platform
• Phishing detection system
• Mail server protection
• Open source email filtering

Headquarters

HQ city

Cambridge

HQ country

United Kingdom

HQ region

Europe

Markets served

GTM type

B2B

Offering type

Software

Cost components

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

Revenue model

1. Open Source Engine: Free open-source spam filtering engine under Apache 2.0 license. Core product distributed freely to build user base and community contributions.
2. Scale Tier: Monthly subscription at £100 + VAT/month for 5K mailboxes. Includes fuzzy premium database, bulk service, Neural/FastText models, Rspamd Console, priority support and SLA.
3. Enterprise Tier: Custom pricing for 50K+ mailboxes with full support including Rspamd Console, Neural/FastText models, custom development & training. Backed by core engineering team.
4. Hosted Tier: Fully managed Rspamd deployment on customer or Rspamd infrastructure. Everything in Enterprise plus managed deployment with custom mailbox counts.
5. Premium Fuzzy Service: Premium fuzzy hashes with longer retention, more sources, and higher accuracy. Lower latency between spamtrap hit and hash placement. Includes rsync-based access to URLs and Emails feeds.

Pricing tiers

Go-to-market motion3 records

Distribution channels3 records

Marketing channels8 records

Core offering

Rspamd provides an open-source email security engine written in C with event-driven asynchronous architecture, delivering multi-layer protection combining reputation filtering, sender authentication (SPF, DKIM, DMARC, ARC), content analysis, Bayesian statistics, neural networks, and fuzzy hashing to detect spam, phishing, malware, and business email compromise. The company also sells premium subscription tiers (Scale, Enterprise, Hosted) that add SLA-backed support, advanced fuzzy hash databases, Neural/FastText models, the Rspamd Console operational dashboard, and fully managed deployment services for organizations.

Product overview

Rspamd is an open-source email security platform built as a high-performance C-based framework with event-driven architecture. The core engine provides multi-layer email protection combining reputation filtering, sender authentication (SPF/DKIM/DMARC/ARC), content analysis, and machine learning (Bayesian classifier, neural networks, fuzzy hashing). The product family consists of the open-source Rspamd Core Engine (Apache 2.0), the Rspamd Console operational dashboard add-on for cluster management, and three Rspamd Premium tiers (Scale, Enterprise, Hosted) that provide enhanced fuzzy databases, Neural/FastText models, priority support with SLAs, rsync DNS zones, and managed deployment options. Premium features build on the open-source foundation to add stronger detection data and direct access to core engineers.

Differentiator

Problem solved

Functional benefit

Products and services

• Rspamd Core Engine High-performance open-source email security engine written in C with event-driven asynchronous architecture, providing spam filtering, phishing detection, malware scanning, and policy enforcement through Bayesian statistics, neural networks, fuzzy hashing, and 60+ analysis modules. Licensed under Apache 2.0 for enterprises, ESPs, and hosting providers.
• Rspamd Console Operational dashboard providing detection-impact analysis, symbol introspection, live mail-stream capture, and LLM-assisted rule authoring for Rspamd clusters. Sold as an add-on within premium plans for security teams running Rspamd at scale.
• Rspamd Premium Scale

Quantifiable outcome

• 10-20x faster spam filtering than SpamAssassin (5-10 msg/sec/core vs 0.5-2)
• +3 more outcomes

Named customers1 record

Segments4 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

Yes

API docs

API detail

Core technology

AI maturity

App detail

Integration10 records

AI capability6 records

Feature7 records

Partnerships

One partnership is on record.

• AbusixsignificantStrategic or Co-development Partner · 16 May 2019Abusix provides spam feeds to improve Rspamd fuzzy storage quality and feeds URLs and Emails to DNS black lists. They support Rspamd project and generously provided their spam intelligence feeds for performance benchmarking, processing approximately 100 million messages per day.

Scale indicators10 records

Recent moves5 records

Expansion highlights4 records

Direct peers

• SpamAssassin (Apache Foundation): Long-standing open-source spam filter written in Perl; Rspamd explicitly benchmarks against it and offers direct SA-rule compatibility for migration. They target the same self-hosted email security use case with the same customer persona.
• MailChannels: Email delivery and security platform focused on hosting providers and ESPs with outbound spam filtering and reputation protection. Strong overlap with Rspamd's Hosting Providers segment and complementary technology stack.

Broad incumbents

• Proofpoint: Leading enterprise email security platform offering anti-phishing, anti-spam, and DLP as part of a broader people-centric security suite. Competes for the same enterprise buyers as Rspamd Premium but with much larger scale and bundle positioning.
• Mimecast: Cloud-based email security, archiving, and continuity provider targeting mid-market and enterprise organizations. Overlaps with Rspamd's enterprise spam/phishing filtering and represents a default incumbent competitor in RFPs.
• Barracuda Networks (Email Security): Provides email protection, archiving, and backup across on-premises and cloud with focus on SMB and mid-market. Competes with Rspamd's Scale and Enterprise tiers in the same anti-spam/anti-phishing category.
• Cisco Secure Email (IronPort): Cisco's enterprise email security portfolio (formerly IronPort) offering on-prem and cloud anti-spam, phishing, and malware filtering. Competes for the same large enterprise mail-server replacement and augmentation deals as Rspamd Premium.
• Microsoft Defender for Office 365: Default enterprise email security for Microsoft 365 tenants, offering anti-phishing, anti-spam, and safe-attachments. Competes head-on in enterprises where bundled Microsoft security is the easiest procurement path.

Emerging players

• Abnormal Security: AI-native email security platform focused on detecting business email compromise, account takeover, and vendor fraud using behavioral ML. Competes for the same AI-driven phishing-detection value proposition Rspamd markets via its LLM integration.
• Hornetsecurity (SpamTitan): European-headquartered email security provider offering SpamTitan and broader 365 protection suites. Directly competes with Rspamd Premium in the SMB and mid-market anti-spam category, especially in EMEA.
• Sublime Security: Open-detection email security platform with community-driven rules similar in spirit to Rspamd's open-source ethos. Targets the same security-team buyer who wants auditable, programmable email detection rather than black-box SaaS.

Market position

Strengths4 records

Weaknesses5 records

Competitive moat6 records

Key risks6 records

Key highlights7 records

Customer concentration

• Xtwitter.com/rspamd
• GitHubgithub.com/rspamd/rspamd
• LinkedInlinkedin.com/company/rspamd-ltd

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

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 RSPAMD LTD