Koios
Free and decentralized Cardano API powered by community nodes
What is Koios?
Koios is a free, decentralized Cardano API powered by a network of community-run nodes. Unlike centralized API providers, Koios has no single point of failure — its elastic query layer is maintained by SPOs and community members, making it a resilient and censorship-resistant alternative for Cardano developers.
Key Features
Completely Free
Koios is free to use with no API keys required for public endpoints — ideal for open-source projects, hackathons, and budget-conscious developers.
Decentralized Node Network
Koios is powered by stake pool operators and community nodes distributed globally. No single entity controls the API, ensuring censorship resistance and high availability.
Elastic Query Layer
Koios uses PostgREST to expose Cardano's full data model as a queryable REST API with filtering, ordering, and pagination — giving developers flexible access to on-chain data.
Community Governed
The Koios API specification and node requirements are governed by the community, with SPOs incentivized to run nodes that serve the public API.
How to Use Koios
- 1
No signup required — make API calls directly to api.koios.rest
- 2
Browse the full API documentation at api.koios.rest/api/v1
- 3
Use query parameters to filter results (e.g. ?_stake_address=stake1...)
- 4
For higher rate limits, run your own Koios node or use a dedicated instance
- 5
Join the Koios community on Telegram for support and updates
Frequently Asked Questions
Is Koios really free?
Yes. Koios public endpoints are free with no API key. Rate limits apply to prevent abuse but are generous for development and moderate production use.
Is Koios reliable for production?
Koios is highly available due to its decentralized nature. For mission-critical applications, consider running your own Koios instance or using multiple API providers.
How does Koios compare to Blockfrost?
Koios is free and decentralized; Blockfrost is centralized but offers webhooks, IPFS, and premium SLAs. Many developers use both — Koios for cost efficiency and Blockfrost for advanced features.
Can I run my own Koios node?
Yes. SPOs and developers can run Koios nodes, contributing to the network's decentralization and earning recognition in the Koios ecosystem.