[!TIP] Looking for detailed guides and tutorials? The complete user guide for Dolos is available at docs.txpipe.io/dolos.

What is Dolos?

Cardano nodes traditionally assume one of two roles: block producer or relay. Dolos introduces a third role: the data node — optimized for keeping an updated ledger and responding to queries while requiring a fraction of the resources.

Dolos connects directly to the Cardano network using Ouroboros Node-to-Node (N2N) mini-protocols (via Pallas). It relies on honest upstream peers rather than performing full consensus validation, enabling significant resource savings.

Why Dolos?

• Low resource footprint — Runs with a small fraction of the memory and CPU required by a traditional Cardano node
• Rich API surface — Multiple protocols to match your existing stack: REST, gRPC, HTTP, JSON-RPC, and Ouroboros
• Flexible storage mode — Choose your data retention: ledger-only, sliding window, or full archive
• Full multi-era support — Handles all Cardano eras from Byron through Conway, including full governance support (DReps, proposals, voting)

Flexibility

Choose your storage profile:

| Profile | Description | Best For | |---------|-------------|----------| | Ledger-only | Current state only (UTxO set, pools, protocol params) — minimal disk | Services needing only current ledger state | | Sliding history | Configurable retention window for recent data | Most dApps that need recent history | | Full archive | Complete chain history from genesis | Explorers, analytics, archival |

Choose your API surface:

| API | Protocol | Best For | |-----|----------|----------| | MiniBF | REST (Blockfrost-compatible) | Existing Blockfrost integrations, wallets, SDKs | | MiniKupo | HTTP (Kupo-compatible) | Pattern-based UTxO matching, chain indexing | | UTxO RPC | gRPC / gRPC-Web | High-performance streaming, browser clients | | TRP | JSON-RPC (Tx3) | Transaction building with Tx3 framework | | Ouroboros | Node-to-Client | cardano-cli compatibility, Ogmios workflows |

Features

Data Capabilities

• Full historical reward logs — Complete reward distribution calculations and epoch state management
• Stake distribution snapshots — Historical stake snapshots and epoch boundary logic
• Pool registry & metadata — Pool registration, retirement handling, and delegator tracking
• Asset registry — Token and NFT metadata tracking with CIP-25 support
• Script indexing — Support of search / retrieval of scripts / datums by hash
• Governance data — DRep registration, proposals, and voting state (Conway era)

Developer Experience

• Mempool-aware transaction submit — Tracks pending, inflight, and finalized UTxO states, enabling transaction chaining workflows
• Local devnet mode — Ephemeral single-node network via for offline development
• Fast Mithril bootstrap — Sync mainnet from Mithril snapshot in under 20 hours
• Dolos snapshots — Export and load node state in minutes for rapid deployment
• Multi-platform binaries — Native packages for macOS (Apple Silicon), Linux (ARM64/x64), Windows x64, plus Docker images

Operations & Observability

• Dual storage backends — Choose between Redb v3 or Fjall LSM-tree based on your workload
• OpenTelemetry integration — Distributed tracing with OTLP export
• Prometheus metrics — Health and performance monitoring endpoints
• Rust implementation — Memory safety, high performance, and small binary size

Architecture

Dolos follows a modular, layered architecture:

• Core abstractions (dolos-core) — Storage traits (State, Archive, WAL, Index), entity-delta system, and batch processing pipeline
• Cardano logic (dolos-cardano) — Era-specific block processing, validation, reward calculation, and UTxO delta computation
• Storage backends — Pluggable implementations: Redb v3 or Fjall LSM-tree
• Service layer — gRPC, REST, and Ouroboros protocol servers

Data is organized into four isolated storage layers: State (current ledger), Archive (historical blocks), WAL (crash recovery), and Index (fast lookups). State mutations use an entity-delta pattern enabling efficient rollbacks without full snapshots.

Quick Start

We highly recommend following the quick start guide on our documentation site for detailed step-by-step instructions.

# macOS
brew install txpipe/tap/dolos

# Linux
curl --proto '=https' --tlsv1.2 -LsSf \
  https://github.com/txpipe/dolos/releases/latest/download/dolos-installer.sh | sh

# Windows (PowerShell)
powershell -c "irm https://github.com/txpipe/dolos/releases/latest/download/dolos-installer.ps1 | iex"

# Docker
docker run ghcr.io/txpipe/dolos:latest

# Node
npm install @txpipe/dolos

Once installed:

dolos init       # Interactive configuration and bootstrapping

📖 Full documentation: https://docs.txpipe.io/dolos

Contributing

PRs are welcome! Please ensure your changes pass CI checks.

See CONTRIBUTING.md for guidelines.

License

Dolos is licensed under the Apache License 2.0. See LICENSE for details.