# google/trillian

A transparent, highly scalable and cryptographically verifiable data store.

Repository: https://github.com/google/trillian
Canonical: https://ross.abutalabs.com/products/trillian
Language: Go
License: Apache-2.0
License Family: permissive
Topics: certificate-transparency, merkle-tree
Last push: 2026-08-25T09:35:37+00:00

## Health v2 (maintenance only)
Score: 83/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 53, longevity 100
- inputs: {"age_days": 3765, "days_push": 8, "days_rel": 156, "gap_med": 105, "n_releases_24m": 4}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3746, forks 460 (observed 2026-08-28T04:08:16.101323+00:00)

## What it is
Trillian is a transparent, cryptographically verifiable append-only data store built on Merkle trees, backed by scalable storage like MySQL. It serves as the core engine for transparency applications such as Certificate Transparency, with application-specific 'personalities' built on top.

## Use cases
- run a certificate transparency log
- build an append-only tamper-evident log
- store data with cryptographic audit proofs
- implement a verifiable transparency application
- serve inclusion proofs for large datasets

## When to choose
- you need a scalable, cryptographically verifiable append-only log
- you are building a Certificate Transparency personality
- you need Merkle-tree-based audit proofs over large datasets

## When to avoid
- you are starting a new transparency log project (prefer Tessera)
- you need a general-purpose mutable database
- you need a small-scale log without verifiability requirements

## Facets
- artifact type: service
- maturity: maintenance
- function: database, security, cryptography
- domain: security, databases, developer-tools
- platform: go, self-hosted
- tags: merkle-tree, certificate-transparency, append-only-log, verifiable-data-structures, transparency-log, linux, docker

## Member repositories
- google/trillian (main) score 83

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:16.101323+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 2026-08-29T18:29:02.856311+00:00, confidence not recorded.
  - readme: https://github.com/google/trillian (fetched 2026-08-28T04:08:16.101323+00:00, sha cf7ed157842e)
- Data as of 2026-08-30T08:39:29.467469+00:00.