What Spiral does

Spiral (formerly Square Crypto) is an internal, non-profit Bitcoin organization within Block Inc. (NYSE: SQ), founded in 2019 by Jack Dorsey and rebranded from Square Crypto in December 2021. It builds and maintains free, open-source developer infrastructure for the Bitcoin ecosystem, most notably the Lightning Development Kit (LDK) and Bitcoin Development Kit (BDK)—Rust-based libraries with multi-language bindings (Kotlin, Swift, Python, Flutter, React Native) that simplify Lightning Network and on-chain Bitcoin wallet development. Supporting products include LDK Node (a ready-to-go Lightning node wrapper), the Bitcoin Design Guide and Community (UX standards and a 2,500+ member Slack), and team contributions to the Stratum V2 mining protocol and Fedimint federated custody.

The organization runs the world's largest FOSS Bitcoin grant program, having issued 70+ grants totaling over $7 million to 40 grantees and 10 projects across 20+ countries. Notable downstream adopters include Cash App (tens of millions of users), Blue Wallet, Mutiny, and BTCPay Server, with dozens of additional wallet developers and exchanges evaluating LDK. Distribution is via GitHub, crates.io, and dedicated documentation sites at lightningdevkit.org and bitcoindevkit.org, with marketing conducted primarily through developer relations, conferences, and community content.

Spiral is wholly owned and funded by Block Inc. and reports no standalone revenue. Its operating model is community-led and developer-relations driven, with editorial independence on grant decisions despite its parent-subsidiary relationship. The core team remains small (1-10 employees with additional named contributors) and the organization does not charge for its software or services.

Name

Spiral

Legal name

Spiral

Website

https://spiral.xyz

Company type

Private

Founded year

2019

Operating status

Operating

Headcount range

1–10 employees

Short description

Spiral is Block Inc.'s internal non-profit Bitcoin organization that builds free, open-source developer tools—principally the Lightning Development Kit (LDK) and Bitcoin Development Kit (BDK)—while running the world's largest FOSS Bitcoin grant program across 20+ countries.

Ownership category

akta.pro rank

Product category

Open-Source Bitcoin Developer Toolkits

NAICS

Grantmaking Foundations (813211)

SIC

Services-Prepackaged Software (7372)

akta.pro primary industry

Smart Contract Frameworks & SDKs (developer kits, templates, standards) (FSAPABAB)

akta.pro secondary industries

Smart Contract Developer Platforms & Tooling (SDKs, APIs, frameworks, indexing) (FSAPAAAH), Deployment, Automation & DevOps (build pipelines, contract deployment tools) (FSAPABAH)

Keywords

• Bitcoin developer toolkits
• Lightning network sdk
• Open-source bitcoin
• Bitcoin grants program
• Lightning development kit

GTM type

B2B

Offering type

Software

Cost components

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

Revenue model

1. Block Funding: Spiral is funded by Block Inc. (formerly Square) as an internal, non-profit Bitcoin organization. They receive funding from Block to operate their grant program and development activities. Spiral does not generate revenue from their open-source software.

Go-to-market motion2 records

Distribution channels3 records

Marketing channels9 records

Core offering

Spiral builds and funds free, open-source Bitcoin projects aimed at making Bitcoin the planet's preferred currency. Its core deliverables are the Lightning Development Kit (LDK) and Bitcoin Development Kit (BDK), open-source Rust-based SDKs that let wallet and application developers integrate Lightning Network and on-chain Bitcoin functionality, supplemented by the global FOSS Bitcoin Grants program that has funded 70+ grants worth over $7 million to developers and designers in 20+ countries.

Product overview

Spiral (formerly Square Crypto) is a bitcoin-focused FOSS company that builds and funds free, open-source projects aimed at making bitcoin the planet's preferred currency. The company operates a dual strategy: developing its own core developer toolkits (Lightning Development Kit / LDK and Bitcoin Development Kit / BDK) while running the world's largest bitcoin-focused grant program funding over 70 grants worth $7M+ to developers and designers across 20+ countries. LDK simplifies Lightning Network integration for wallet developers while BDK handles on-chain bitcoin wallet development—both are offered as open-source libraries with multi-language bindings. Supporting these developer tools is the Bitcoin Design Guide and Community, providing UX best practices for the ecosystem. Spiral also funds independent projects like BTCPay Server, CoinSwap, Fedimint, Stratum V2, and Summer of Bitcoin internship program.

Differentiator

Problem solved

Functional benefit

Brands

• Lightning Development Kit (LDK): An open-source developer kit that simplifies how developers add Lightning Network capabilities to bitcoin wallets and applications.
• Bitcoin Development Kit (BDK)
• Who is Bitcoin?
• FOSS Bitcoin Grants

Products and services

• FOSS Bitcoin Grants Program Open-source Bitcoin grant program that funds developers and designers in over a dozen countries to work full-time on Bitcoin Core, Lightning Network, privacy, security, and UX projects. To date, Spiral has issued 70+ grants worth over $7 million to 40 grantees across 20+ countries.
• Lightning Development Kit (LDK) Open-source developer library, built on Rust-Lightning, that simplifies how wallet and application developers add Lightning Network capabilities to their products. Includes API, language bindings, demo apps, and comprehensive documentation. Adopted by Cash App, Blue Wallet, Mutiny, and dozens of other wallet projects.
• Bitcoin Development Kit (BDK) Open-source developer library that simplifies how developers build on-chain Bitcoin wallets across platforms, with language bindings for Kotlin, Swift, Python, Flutter, and React Native. Supports desktop hardware signers via HWI integration and provides block chain access via bitcoind RPC and Electrum.
• LDK Node Ready-to-go Lightning node implementation that wraps and simplifies the full suite of LDK APIs, designed for projects needing minimal customization to quickly get started with Lightning.

Named customers5 records

Segments3 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration4 records

Feature6 records

Partnerships

Four partnerships are on record, tiered core and minor.

• BTCPay ServercoreStrategic or Co-development Partner · 14 September 2019BTCPay Server was Spiral's first grant recipient, receiving $100,000. They are an open-source payments processor that lets merchants accept Bitcoin, control their private keys, and self-validate their coins. BTCPay exemplifies open-source Bitcoin community ideals and promotes adoption.
• Block (TBD and Bitkey)coreStrategic or Co-development PartnerSpiral works within Block's broader Bitcoin ecosystem alongside TBD (Block's decentralized Bitcoin initiative) and Bitkey (Block's hardware wallet). They share the goal of making Bitcoin a widely used medium of exchange rather than just an investment.
• BrinkminorStrategic or Co-development PartnerSpiral collaborates with Brink, another Bitcoin-focused funding organization, on shared goals of supporting Bitcoin Core developers and the broader open-source ecosystem.
• Bitcoin Core Development Funding OrganizationsminorStrategic or Co-development PartnerSpiral is one of 13 major funding organizations supporting Bitcoin Core development, alongside Blockstream, Chaincode Labs, MIT's Digital Currency Initiative, OKX, Human Rights Foundation, Brink, Btrust, OpenSats, Vinteum, Maelstrom, B4OS, and 2140.

Scale indicators5 records

Recent moves7 records

Expansion highlights5 records

Direct peers

• Chaincode Labs: Chaincode Labs funds and employs Bitcoin Core and Lightning developers, hosts residencies, and contributes to Bitcoin infrastructure — directly comparable to Spiral's combination of FOSS developer employment and grantmaking.
• Brink: Brink is a Bitcoin-only nonprofit that funds and supports Bitcoin Core and Lightning developers through grants and salaries — overlapping mission and funding mechanism with Spiral's grant and developer programs.
• OpenSats: OpenSats is a 501(c)(3) that issues FOSS grants to Bitcoin and Lightning developers via a similar long-tail grantmaking model to Spiral's, though without Spiral's in-house SDK products.
• Lightning Labs: Lightning Labs builds LND, a leading Lightning Network implementation, and operates developer-facing Lightning infrastructure — directly competing with Spiral's LDK for Lightning wallet developer mind-share.
• MIT Digital Currency Initiative: DCI is one of the 13 major Bitcoin Core funding organizations alongside Spiral, employing researchers and developers to work on Bitcoin Core, Lightning, and ZK proofs.
• Btrust: Btrust funds and trains Bitcoin developers (with an Africa focus) and is one of the 13 Bitcoin Core funding organizations listed alongside Spiral — directly comparable mission and constituency.
• Human Rights Foundation (Bitcoin Development Fund): HRF's Bitcoin Development Fund provides grants and residencies to global Bitcoin developers focused on freedom tech — same FOSS grantmaking model as Spiral's program.

Broad incumbents

• Blockstream: Blockstream is a larger, for-profit Bitcoin infrastructure company building Core Lightning, Liquid, mining infrastructure, and enterprise Bitcoin services — broader scope but overlapping Lightning development territory.

Others

• Bitkey: Bitkey is Block Inc.'s self-custodial Bitcoin hardware wallet product and a sister organization within Block — relevant because Spiral-developed tools feed Bitkey's product roadmap and the two share a corporate parent.

Emerging players

• Maelstrom: Maelstrom is a Bitcoin-native investment firm that both invests in and funds Bitcoin open-source development — listed among the 13 Bitcoin Core funding organizations alongside Spiral with a more investor-oriented angle.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks5 records

Key highlights7 records

Customer concentration

• Xx.com/spiralbtc
• YouTubeyoutube.com/@herecomesbitcoin
• LinkedInlinkedin.com/company/spiralbtc

Revenue estimate

Valuation estimate

Number of profiles

Profiles13 records

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 Spiral