Elastic Cardano Query Layer!

A consistent query layer for developers to build upon Cardano, with multiple, redundant endpoints that allow for easy scalability.
Our Mission
What is Koios REST API?

Resource and maintenance requirements for Cardano blockchain components (e.g. cardano-node, cardano-db-sync) are ever-growing. Along with that, every builder needs to identify how to query complex information from the chain.

Minimum requirements

We want to provide the developer with a data layer that they can rely on without having to constantly reinvent the wheel.

Data standards

Some queries are very complex and therefore prone to errors. We want to make them available in a standardised way – also via future hardforks.

Failover support

You can rely on Koios! That’s why all access points, front-end and back-end nodes are designed with multiple redundancy. There is no central instance..


If you have a good idea and want to implement it with Cardano, you should concentrate fully on it and get started straight away. Koios helps you to do this.

Project Koios

Frequently Asked Questions

The name Koios – derived from ancient Greek ‘Κοιος’ – meaning “question,” “inquiry,” or “inquisitiveness.” is the Titan of Resolve and Intelligence and also a god of heavenly oracles.

It will be increasing list of community builders. But for initial think-tank and efforts, the work done is primarily by guild-operators who are well recognised team of members behind tools like CNTools, gLiveView, topology Updater, etc. We also run a parallel a short (30-min) epoch blockchain, viz, guild used by many for experiments.

For most of the queries, there are no charges. But there are DDoS protection and strict timeout rules that may prevent heavy consumers from using this remotely (for which, there should be an interaction to ensure the usage is proportional to sizing and traffic expected).

All the Postgres codebase against dbsync instance is available on guild-operator’s github repo here. Feel free to raise an issue/PR to discuss anything related to those queries.

Read more about the Koios architecture at https://api.koios.rest/

Projects using Koios

Eternl light wallet
Eternl light wallet