Tarsnap

What Tarsnap does

Tarsnap is a privately held, founder-operated online backup service founded by Colin Percival in 2008, targeting users of UNIX-like operating systems (Linux, FreeBSD, NetBSD, OpenBSD, macOS, Cygwin, WSL). Its core product is a command-line backup client built on libarchive and FreeBSD's bsdtar, augmented with proprietary deduplication via variable-length content-defined chunking, DEFLATE compression, and multi-layer cryptography (RSA-2048 signing, RSAES-OAEP session key encryption, AES-256-CTR data encryption, HMAC-SHA256 block authentication). The Tarsnap 1.0.41 release (March 2025) added PADME padding and small-alphabet cycle prohibitions to defend against a newly published class of chosen-plaintext chunking attacks. Immutable, server-side archives are deduplicated across the user's own corpus, yielding reported reductions of 99.94% on hourly backups and 93.3% on personal data, and a local cache directory (~0.5% of stored data size) enables fast subsequent runs.

The business model is a pure usage-based prepaid model billed at $0.25/GB-month of encoded storage and $0.25/GB of bandwidth, with no fixed fees or minimums; over half of users spend under $1/month. Distribution is entirely self-serve via direct download from tarsnap.com, with integrations into Docker, Chef, Puppet, Ansible, and Heroku, plus a third-party helper-script ecosystem. There are no disclosed funding rounds, no enterprise sales motion, and no marketing spend; growth is community-led through mailing lists, IRC, GitHub, and the founder's reputation as FreeBSD Security Officer Emeritus. Tarsnap is incorporated as Tarsnap Backup Inc. in Canada and runs on a single AWS EC2 instance backed by Amazon S3 standard durability storage.

Name

Tarsnap

Legal name

Tarsnap Backup Inc.

Website

https://tarsnap.com

Company type

Private

Founded year

2008

Operating status

Operating

Headcount range

1–10 employees

Short description

Tarsnap is a founder-operated, prepaid online backup service for UNIX-like systems (Linux, BSD, macOS, WSL) that combines client-side encryption, variable-length content-defined chunking deduplication, and immutable archives, serving security-conscious technical users via a pure self-serve model with usage-based pricing.

Ownership category

akta.pro rank

Product category

Cloud Backup Services

NAICS

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

SIC

Services-Computer Processing & Data Preparation (7374)

akta.pro primary industry

Cloud Storage Core Services (Object/Block/File Storage as a Service) (HDABAAAK)

akta.pro secondary industry

Cyber Recovery & Ransomware-Resilient Backup Services (BPAEALAG)

Keywords

• Online backup service
• Encrypted cloud storage
• Command-line backup
• Deduplicated data backup
• UNIX backup software

Headquarters

HQ city

Burnaby

HQ country

Canada

HQ region

North America

Offices1 record

Markets served

GTM type

B2C

Offering type

Software

Cost components

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

Revenue model

1. Cloud Backup Storage & Bandwidth: Pay-per-use model where customers pay for actual storage consumed (encoded bytes after deduplication and compression) and bandwidth used. No fixed fees, minimums, or monthly charges. Prepaid account balance model similar to mobile phones.

Pricing tiers

Go-to-market motion2 records

Distribution channels1 record

Marketing channels6 records

Core offering

Tarsnap is an encrypted, deduplicated command-line online backup service for Linux, FreeBSD, NetBSD, OpenBSD, macOS, Cygwin, WSL, and other UNIX-like operating systems. It performs client-side encryption, content-defined chunking-based deduplication, and compression before transmitting data to Tarsnap-managed servers backed by Amazon S3, charging customers a prepaid usage-based fee for storage and bandwidth with no minimums or fixed costs. Companion open-source projects (scrypt, kivaloo, spiped) and key management utilities (tarsnap-keygen, tarsnap-keymgmt, tarsnap-keyregen, tarsnap-recrypt) support the core service.

Product overview

Tarsnap is a single unified product: an encrypted, deduplicated command-line online backup service for UNIX-like systems. The core Tarsnap client software is supplemented by key management utilities (tarsnap-keygen, tarsnap-keymgmt, tarsnap-keyregen, tarsnap-recrypt) for cryptographic key lifecycle management. Tarsnap also publishes several open-source components developed during its creation under BSD license: the scrypt key derivation function (with accompanying encryption utility), the kivaloo data store library, and the spiped secure pipe daemon. Third-party helper scripts automate backup rotation and integration with configuration management tools. The service uses a prepaid billing model with per-byte storage and bandwidth pricing.

Differentiator

Problem solved

Functional benefit

Brands

• scrypt: A password-based key derivation function designed to be more secure against hardware brute-force attacks than PBKDF2 or bcrypt. Originally developed for Tarsnap and published as open source under BSD license.
• spiped
• kivaloo

Products and services

• Tarsnap Online Backup Service Encrypted, deduplicated command-line online backup service for Linux, FreeBSD, NetBSD, OpenBSD, macOS, Cygwin, WSL, and other UNIX-like operating systems. Performs client-side encryption, content-defined chunking-based deduplication, and compression before transmitting data to AWS-hosted servers backed by Amazon S3, charging a prepaid usage-based fee.
• tarsnap-keygen Standalone key generation utility that creates cryptographic keys, registers them with the Tarsnap server, and writes a key file for use with the Tarsnap backup client.
• tarsnap-keymgmt Standalone key management utility that generates subsets of Tarsnap key files with reduced permissions (read-only, write-only, delete-individual, or nuke) for security compartmentalization.
• tarsnap-keyregen Standalone re-encryption key generation utility that produces cryptographic keys compatible with existing keys for re-encrypting archives with new keys.
• tarsnap-recrypt Standalone re-encryption utility that downloads and decrypts data using old keys and re-encrypts and uploads it using new keys, enabling key rotation without data loss.
• scrypt Key Derivation Function Standalone memory-hard password-based key derivation function originally developed for Tarsnap, designed to be more secure against hardware brute-force attacks than PBKDF2 or bcrypt. Published as open source under BSD license and standardized as IETF RFC 7914.
• scrypt Encryption Utility Standalone simple password-based encryption utility demonstrating the scrypt key derivation function, providing strong encryption for files using scrypt-derived keys.
• kivaloo Data Store Standalone data store library developed as a reusable component of Tarsnap's infrastructure, published separately under BSD license.
• spiped Secure Pipe Daemon Standalone utility for creating symmetrically encrypted and authenticated pipes between socket addresses, similar to 'ssh -L' functionality but without using SSH. Uses HMAC-SHA256 and authenticated Diffie-Hellman key exchange with AES-256 in CTR mode.

Quantifiable outcome

• 96,502 GB of backups deduplicates to 56.1 GB (99.94% reduction)
• +3 more outcomes

Named customers1 record

Segments2 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration6 records

Feature7 records

Partnerships

Seven partnerships are on record, tiered minor and core.

• BSD NowminorOthers · 1 May 2014Weekly BSD podcast receiving sponsorship since May 2014.
• Simon Fraser UniversityminorOthers · 1 January 2014Annual sponsorship of Simon Fraser University's Open Source Software Engagement Award since 2014.
• BSDCanminorOthers · 1 January 2012Annual sponsorship of BSDCan conference since 2012, plus FreeBSD Developer Summits at BSDCan since 2014.
• FreeBSD FoundationminorOthers · 1 January 2009Tarsnap donates an amount equal to its December gross profits annually to support open source software. FreeBSD Foundation has received annual sponsorship since 2009.
• libarchivecoreTechnology or IntegrationTarsnap uses the libarchive library (BSD-licensed) for reading files from disk. Tarsnap contributes patches back to the project.
• FreeBSDcoreTechnology or IntegrationTarsnap client is built on FreeBSD's bsdtar and libarchive. Tarsnap contributes patches back to FreeBSD.
• Amazon S3coreTechnology or IntegrationTarsnap stores encrypted data on Amazon S3 (standard durability, not reduced redundancy). This is the underlying storage infrastructure for the service.

Scale indicators5 records

Recent moves6 records

Expansion highlights4 records

Direct peers

• Backblaze: Backblaze offers consumer and B2 cloud backup/storage with a similar usage-friendly model. It is the closest mass-market analog to Tarsnap in online backup, even though Backblaze targets a broader, less technical audience.
• BorgBase (by The Boring Company / Borgify): BorgBase hosts Borg (deduplicated, encrypted) repositories. It directly competes on the same core value propositions Tarsnap advertises — client-side encryption and deduplication — but with an open-source client.
• rsync.net: rsync.net provides UNIX-focused offsite backup using rsync/zfs over SSH, appealing to the same sysadmin persona as Tarsnap. Comparable business model and customer base, with strong overlap on technical users.

Broad incumbents

• AWS Backup: AWS Backup is a native, centralized backup service across AWS services. As Tarsnap itself runs on AWS, AWS Backup represents both an upstream infrastructure partner and a potential competitive substitute for cloud-native workloads.
• Acronis: Acronis combines backup, anti-ransomware, and cyber protection for consumers through enterprise. It is a much larger incumbent with overlapping capabilities (encrypted, immutable backup) and broader platform support.
• Veeam: Veeam is a dominant enterprise backup vendor for virtualized and cloud workloads. It competes for the server backup use case Tarsnap addresses for technical users, but at a vastly larger scale and with enterprise features.
• CrashPlan (Code42): CrashPlan offers endpoint and server backup with continuous versioning, serving both SMB and enterprise customers. It overlaps with Tarsnap on continuous, encrypted backup but with a much broader product and sales footprint.

Emerging players

• Restic: Restic is an open-source, encrypted, deduplicated backup tool with a community of hosted providers. It targets similar UNIX/CLI workflows and could either be a complement or a substitute for Tarsnap.
• Duplicati: Duplicati is a free, open-source backup client with encryption, deduplication, and many storage backends. It competes for the same self-hosted/technical-user persona and overlaps with Tarsnap's feature set.
• Wasabi: Wasabi is a low-cost S3-compatible object storage provider often used as a backup target. It is not a direct backup service but is adjacent infrastructure for self-managed backup stacks that compete with Tarsnap.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat5 records

Key risks6 records

Key highlights6 records

Customer concentration

• Xx.com/tarsnap
• GitHubgithub.com/Tarsnap/tarsnap

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 Tarsnap