Cardano API

Overview

Cardano API is a Haskell library that provides the core Cardano API interface used by Cardano tools like the node, CLI, and other Haskell-based services. It exposes high-level functions to build and interact with Cardano types (transactions, addresses, queries) without dealing with low-level internals.

Important: cardano-api is not a REST API or external HTTP API — it's a library you import into Haskell code.

Repository

github.com/IntersectMBO/cardano-api

What It Does

Cardano API provides a unified interface that integrates ledger, consensus, and networking repositories into a single API. It serves as essential building blocks for Cardano node and application development with strongly-typed Haskell interfaces for reliable blockchain interactions.

Key Components

Component	Description
cardano-api	Main API library
cardano-api-gen	Code generation utilities
cardano-rpc	Remote Procedure Call interface
cardano-wasm	WebAssembly bindings

When to Use It

Use cardano-api when building Haskell applications that need to:

• Build and sign transactions programmatically
• Work with addresses, keys, and ledger types
• Query chain data via a connected Cardano node
• Serialize/deserialize Cardano data (CBOR/JSON)
• Interact with multiple Cardano eras (Byron, Shelley, etc.)
• Include smart contract (Plutus) functionality

This library provides consistent types and helpers to work with the blockchain without rewriting Cardano internals.

Use Cases

Use Case	Example Applications
Node Development	Full nodes, relay nodes, block producers
Wallet Development	Desktop wallets, mobile wallets, hardware wallet integrations
CLI Tools	Transaction builders, query tools, governance utilities
DApp Backends	DeFi platforms, NFT marketplaces, governance systems
Blockchain Explorers	Block explorers, analytics dashboards, monitoring tools
Infrastructure Services	Indexers, oracles, bridge services, staking pools
Smart Contract Tools	Contract compilers, testing frameworks, deployment tools
Governance Systems	Catalyst voting, on-chain governance, treasury management

Technical Details

Aspect	Details
Language	Haskell (96.6%)
License	Apache-2.0
Build System	Cabal, Nix
Documentation	Haddock

Getting Started

Prerequisites

• GHC (Glasgow Haskell Compiler) version 9.2 or later
• Cabal or Stack as build tool
• Nix (recommended for Cardano development)

Adding as a Dependency

Using Cabal:

Add to your .cabal file:

build-depends:
    base >= 4.14 && < 4.22,
    cardano-api >= 10.0

Or add to cabal.project:

source-repository-package
  type: git
  location: https://github.com/IntersectMBO/cardano-api.git
  tag: <version-tag>

Using Stack:

Add to stack.yaml:

extra-deps:
  - git: https://github.com/IntersectMBO/cardano-api.git
    commit: <commit-hash>

Note: Align versions with what's published on CHaP (Cardano Haskell Package index).

Basic Usage

Import the library:

import Cardano.Api
import Cardano.Api.Shelley

Key modules provide:

• Transaction building and signing
• Address handling and validation
• Protocol parameter queries
• Serialization/CBOR helpers
• Chain querying functions

Common Modules

Module	Purpose
Cardano.Api	Core API types and functions
Cardano.Api.Shelley	Shelley-era specific functionality
Cardano.Api.Byron	Byron-era compatibility
Cardano.Api.Address	Address creation and validation
Cardano.Api.TxBody	Transaction body building
Cardano.Api.Tx	Transaction construction and signing
Cardano.Api.Query	Chain querying functions

Best Practices

1. Error Handling: Always handle Maybe and Either types returned by API functions
2. Network IDs: Use appropriate network identifiers (Mainnet, Testnet, etc.)
3. Type Safety: Leverage Haskell's type system for compile-time safety
4. Resource Management: Properly close connections and handle exceptions
5. Testing: Use testnet for development before mainnet deployment

When NOT to Use It

If you don't want to write Haskell or don't want to run a node, consider these alternatives:

• Blockfrost - REST API for JS/Python/any language
• Koios - Community-driven REST API for Cardano
• Cardano GraphQL - GraphQL API for querying Cardano data
• Ogmios - WebSocket API for Cardano node interaction

cardano-api is specifically for Haskell development and local node interaction.

Summary

Feature	Supported
Build transactions	Yes
Serialize/Deserialize	Yes
Chain queries	Yes (with node connection)
REST endpoint	No
JavaScript/Python use	Not directly

Workflow

1. Run a Cardano node (locally or via service)
2. Import cardano-api in your Haskell project
3. Use its types/functions to build transactions, query ledger state, and process keys/addresses
4. Submit transactions via cardano-submit-api or direct submission through the node

Deeper Documentation

• Haddock Documentation

Contributing

This repository welcomes contributions. See the Contributing Guide for details on code of conduct, development workflow, pull request process, and testing requirements.