Splinter v0.4 Release

Splinter v0.4 is a major new release. Here’s a summary of the new and noteworthy features in this release. For detailed changes related to the v0.4 release, see the Splinter release notes.

If you’re new to Splinter, see the Splinter documentation to learn about Splinter concepts and features.

New and Noteworthy

API Stability

The Splinter v0.4 release commits to API stability. Changes in future v0.4.x releases will be backward compatible with release v0.4, so that application developers can rely on the existing behavior and features of the Splinter APIs.

Splinter API stability includes the REST API, the CLIs (splinter, splinterd, and scabbard), the application interfaces of the splinter library, and communication between peers.

Robust Circuit Support

A circuit is a virtual network within the broader Splinter network that safely and securely enforces privacy scope boundaries. The admin service manages circuits and circuit proposals on each node, using two-phase commit protocol for consensus.

Splinter now includes robust support for managing circuits directly with CLI tools and REST API endpoints, as well as the ability to delegate circuit control to your application.

Circuits managed by CLIs and REST API

For command-line interaction, splinter circuit provides the following subcommands to create and manage circuits, vote on proposed circuits, and display circuit information. For more information, see the Splinter CLI Command Reference.

  • list: Lists all circuits that the node belongs to

  • proposals: Lists all circuit proposals for the node

  • propose: Proposes the creation of a new circuit

  • show: Displays a specific circuit or circuit proposal

  • vote: Votes to accept or reject a circuit proposal

The REST API provides the following endpoints for circuits and circuit proposals. For more information, see the splinterd REST API Reference.

  • GET /admin/circuits: Fetches a list of the circuits that the node belongs to

  • GET /admin/circuits/{circuitID}: Fetches information about a specific circuit

  • GET /admin/proposals: Fetches a list of the proposed circuits for the node

  • GET /admin/proposals/{circuitID}: Fetches information about a specific circuit proposal

Circuit management can be delegated to applications

For applications that need more control over circuit creation and management, Splinter supports the ability to delegate circuit control to your application. For example, an application could control whether (and when) to propose and authorize new circuits.

Registry for Local and Remote Node Information

In previous releases, Splinter used a node registry to store node-related information and a separate key registry to store the public and encrypted private keys associated with those nodes.

In this release, the unified Splinter registry combines node and key information from local and remote files. The Splinter daemon constructs the local registry from a local registry file and multiple (zero or more) remote registry URLs. For more information, see the v0.3.17 upgrade document and the splinterd(1) man page.

Biome for User Management

Biome handles all user-related functionality so that the rest of Splinter doesn’t have to know anything about users and their access credentials. All other Splinter components are key-based – for example, keys are used to sign transactions rather than user IDs and passwords. Biome handles all user-related information and provides the user keys that the rest of Splinter relies on.

Splinter exposes several /biome REST API endpoints for registering users, accessing user information, updating passwords (or other access credentials) and more. See Biome User Management and the /biome endpoints in the splinterd REST API Reference.

Scabbard Service for Smart Contract Execution

Scabbard is a Splinter service that runs the Sabre smart contract engine using Hyperledger Transact for state management. Scabbard uses two-phase consensus to reach agreement on transactions. The Scabbard service loads contracts from smart contract archive (.scar) files and handles state agreement for those smart contracts.

Splinter uses the following Hyperledger projects for smart contract support:

  • Sawtooth Sabre: Implements on-chain smart contracts that are executed in a WebAssembly virtual machine )
  • Transact: Platform-agnostic library for executing transactions with smart contracts

The scabbard library is packaged as a separate crate available at crates.io.

For command-line interaction, the scabbard CLI provides the following subcommands. For more information, run scabbard --help at the command line.

  • contract: List, show, or upload a Sabre smart contract
  • cr: Create, update, or delete a Sabre contract registry
  • delete: Remove a Sabre namespace
  • exec: Run a Sabre smart contract
  • ns: Create a Sabre namespace
  • perm: Set or remove permissions for a Sabre namespace
  • state: Get scabbard state information

The REST API provides the following endpoints for scabbard. For more information, see the splinterd REST API Reference.

  • POST /scabbard/{circuit}/{serviceID}/batches: Submits a list of batched transactions to the scabbard service
  • GET /scabbard/{circuit}/{serviceID}/batch_statuses: Fetches the status for one or more batched transactions
  • GET /scabbard/{circuit}/{serviceID}/state: Fetches a list of entries from scabbard’s state
  • GET /scabbard/{circuit}/{serviceID}/state/{address}: Fetches a state value at the specified address from scabbard’s state

Configuration Tools for the Splinter Daemon

The Splinter daemon, splinterd, provides Splinter functionality for a node. The daemon can be configured with environment variables, configuration files, and options with splinterd command. For more information, run man splinterd at a command-line prompt or see the Splinter CLI Command Reference.

Peer Management Improvements

Peering is the process of establishing connections from one Splinter node to the other nodes on a circuit.

  • Splinter now uses a dedicated connection manager to provide consistent reconnection and heartbeat logic for both network and component connections.

  • Peering is now performed at the network layer, rather than by the admin service. A dedicated peer manager handles peer connection more reliably.

  • Splinter now supports TCP (HTTP), TCPS (HTTPS), and WebSocket (WS) connections.

Gameroom Example Application

This release includes an example application, Gameroom, that demonstrates how to use Splinter features such as Biome, scabbard, and others.

For more information, see the Gameroom Walkthrough and examples/gameroom in the Splinter repository.

And More

CLIs for splinter, splinterd, and scabbard

This release includes the following command-line tools:

  • splinter: Command-line interface for user and administrator tasks, such as generating keys, working with the Splinter registry, and much more. (This command was called splinter-cli in earlier releases.)

  • splinterd: Command-line interface for running the Splinter daemon.

  • scabbard: Command-line interface for the scabbard service, which manages and runs smart contracts.

For more information, see the Splinter CLI Command Reference. Splinter also provides man pages for these CLI tools; view them by running man {command-subcommand} at a command-line prompt (for example, man splinter-circuit-vote).


This release includes documentation for Splinter concepts, features, and tasks (under development), API reference guides, CLI man pages, and a comprehensive walkthrough for the Gameroom example application.

Splinter Software

Splinter is open-source software that is available on GitHub in Cargill/splinter. Prebuilt Docker images are published on splintercommunity.

For information on building and running Splinter, see the Splinter README.