# bitcoinj/bitcoinj

A library for working with Bitcoin

Repository: https://github.com/bitcoinj/bitcoinj
Canonical: https://ross.abutalabs.com/products/bitcoinj
Homepage: https://bitcoinj.org
Language: Java
License: Apache-2.0
License Family: permissive
Topics: java, bitcoin, library, blockchain, bech32, segwit, bip32, bip37, bip70, bip141, bip143, bip144, bip173, bitcoinj, taproot
Last push: 2026-08-26T20:49:41+00:00

## Health v2 (maintenance only)
Score: 89/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 70, longevity 100
- inputs: {"age_days": 4670, "days_push": 7, "days_rel": 121, "gap_med": 44, "n_releases_24m": 4}
- flags: no_readme
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 5228, forks 2562 (observed 2026-08-28T04:09:13.325195+00:00)

## What it is
bitcoinj is a Java library for working with the Bitcoin protocol, supporting wallet management, sending and receiving transactions via SPV without a local Bitcoin Core copy, and full verification mode. It can be used from any JVM language and includes features like BIP32 key derivation, Segwit, Taproot, and micropayment channels.

## Use cases
- build a Bitcoin wallet app for Android
- send and receive Bitcoin transactions from a JVM application
- implement SPV lightweight Bitcoin verification on constrained devices
- create micropayment channels between client and server
- work with BIP32 hierarchical deterministic keys
- parse and construct Bitcoin transactions and scripts
- build a Bitcoin payment service without running Bitcoin Core

## When to choose
- you need to embed Bitcoin functionality in a Java, Kotlin, Scala, or other JVM application
- you want SPV mode for smartphone or resource-constrained wallets
- you need support for modern Bitcoin features like Segwit, Bech32, and Taproot
- you want a well-documented library with a large ecosystem of existing apps

## When to avoid
- you need a stable API - bitcoinj's API changes between versions
- you require high-performance wallet handling for heavy transaction volumes - the wallet loads all relevant transactions into memory
- you need full node consensus verification in production - full verification mode is experimental
- you are not working on the JVM and cannot use Java interoperability

## Facets
- artifact type: library
- maturity: active
- function: cryptography, security, networking, serialization, sdk
- domain: blockchain, fintech, developer-tools, cross-platform
- platform: jvm, cross-platform
- tags: bitcoin, spv, wallet, blockchain, bip32, segwit, taproot, payment-protocol, micropayment-channels, cryptocurrency, android

## Member repositories
- bitcoinj/bitcoinj (main) score 89

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:13.325195+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:59:40.363843+00:00, confidence not recorded.
  - homepage: https://bitcoinj.org (fetched 2026-08-29T08:55:00.943065+00:00, sha a6a0d3fafcf1)
  - site_page: https://bitcoinj.org/getting-started (fetched 2026-08-29T08:55:00.952302+00:00, sha 9698b8d42359)
  - site_page: https://bitcoinj.org/javadoc/0.17.1 (fetched 2026-08-29T08:55:00.954258+00:00, sha 21df3d3d9398)
  - site_page: https://bitcoinj.org/limitations (fetched 2026-08-29T08:55:00.956063+00:00, sha e72d4676d0ee)
- Data as of 2026-08-30T08:39:29.467469+00:00.