hydra is a free, open source identity & access management (iam) project written in Go and released under Apache-2.0. It has 17,646 GitHub stars, 1,620 forks and 98 open issues, and was last pushed 3 months ago. On this registry it ranks #9 of 70 tracked projects in Identity & Access Management (IAM), with 5 head-to-head comparisons available. It gained 66 stars over the last 30 tracked days.

What is hydra?

Ory Hydra is an OpenID Certified OpenID Connect and OAuth 2.1 provider written in Go and licensed under Apache-2.0, built for teams that need standards-compliant token issuance, client management, and consent flows while user accounts stay in their own existing identity system.

What it is

Ory Hydra is a hardened server implementation of the OAuth 2.0 authorization framework and OpenID Connect Core 1.0. It is deliberately a standalone authorization server without user management: it does not store identities, profiles, or passwords, and instead connects to whatever identity provider already exists through a login and consent app that the operator writes. That app lets the operator keep absolute control over the user interface and experience flows, and Hydra works with any authentication endpoint, including Ory Kratos, authboss, User Frosting, or a proprietary system.

The concrete problem it solves is the cost of building and maintaining an authorization server by hand. Token issuance and validation, client management, consent and login flow orchestration, and JWKS management are the parts of OAuth 2.0 and OpenID Connect that are easy to get subtly wrong and expensive to keep current with the specifications. Hydra replaces that hand-rolled work with a server that implements the IETF and OpenID Foundation standards, follows cloud architecture best practices, and fits modern cloud native environments such as Kubernetes and managed platforms.

Key capabilities

  • Implements the OAuth 2.0 Authorization Framework (RFC 6749), plus the OAuth 2.0 Threat Model and Security Considerations (RFC 6819).
  • Supports OAuth 2.0 Token Revocation (RFC 7009) and OAuth 2.0 Token Introspection (RFC 7662).
  • Covers OAuth 2.0 for Native Apps and Proof Key for Code Exchange (RFC 7636) for public clients.
  • Offers OAuth 2.0 Dynamic Client Registration and its management counterpart (RFC 7591 and RFC 7592).
  • Issues and validates tokens using the JSON Web Token profile for client authentication and authorization grants (RFC 7523).
  • Implements OpenID Connect Core 1.0, OpenID Connect Discovery 1.0, and OpenID Connect Dynamic Client Registration 1.0.
  • Handles OpenID Connect Front-Channel Logout 1.0 and Back-Channel Logout 1.0, and manages JWKS.
  • Exposes headless APIs for integration with existing user management, and ships a Docker-based deployment path.

Who uses it and how

  • Organizations that already own an identity store use Hydra behind that store, wiring Ory Kratos, authboss, User Frosting, or a proprietary system into the login and consent app.
  • Teams running cloud native infrastructure deploy Hydra next to Kubernetes workloads and managed platforms, where its low latency, high throughput, and low resource consumption matter.
  • Operators that need login screens, consent copy, and branding under their own control use the login and consent app boundary to own the entire user-facing flow.
  • Deployments serving large numbers of clients and tokens rely on Hydra for authorization server duties while user management stays elsewhere.
  • The project is trusted by OpenAI and many others for scale and security.

Getting started

Consume Hydra as a service on Ory Network, or self-host it; the README points to the Ory Hydra introduction docs and a quickstart, and Docker appears among the project topics as the container path.

How it compares

The facts name no paid products that Hydra replaces. Within the Ory ecosystem, Ory Kratos handles identity and user management, Ory Oathkeeper is an identity and access proxy, and Ory Keto serves access control policies as a server, while Hydra handles only OAuth 2.0 and OpenID Connect. Outside that ecosystem, projects such as authboss and User Frosting are named as authentication endpoints Hydra can sit behind rather than as substitutes for it.

When to use it — and when not

A self-hoster must operate the Hydra server itself and also design and run the login and consent app, because Hydra deliberately ships no user management and no built-in login interface. Teams that want identity storage, password handling, and a ready-made user interface in one package should look at an identity management system instead of Hydra, and anyone unwilling to own an authorization server's operational surface should prefer the hosted Ory Network option. The registry data shows 98 open issues, so the project carries an active but not empty issue backlog.

project readme (upstream, from github) — read inline

Ory Hydra - Open Source OAuth 2 and OpenID Connect server

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Ory Hydra is a hardened, OpenID Certified OAuth 2.0 Server and OpenID Connect Provider optimized for low-latency, high throughput, and low resource consumption. It connects to your existing identity provider through a login and consent app, giving you absolute control over the user interface and experience.


What is Ory Hydra?

Ory Hydra is a server implementation of the OAuth 2.0 authorization framework and the OpenID Connect Core 1.0. It follows cloud architecture best practices and focuses on:

  • OAuth 2.0 and OpenID Connect flows
  • Token issuance and validation
  • Client management
  • Consent and login flow orchestration
  • JWKS management
  • Low latency and high throughput

We recommend starting with the Ory Hydra introduction docs to learn more about its architecture, feature set, and how it compares to other systems.

Why Ory Hydra

Ory Hydra is designed to:

  • Be a standalone OAuth 2.0 and OpenID Connect server without user management
  • Connect to any existing identity provider through a login and consent app
  • Give you absolute control over the user interface and experience flows
  • Work with any authentication endpoint: Ory Kratos, authboss, User Frosting, or your proprietary system
  • Scale to large numbers of clients and tokens
  • Fit into modern cloud native environments such as Kubernetes and managed platforms

OAuth2 and OpenID Connect: Open Standards

Ory Hydra implements Open Standards set by the IETF:

and the OpenID Foundation:

OpenID Connect Certified

Ory Hydra is an OpenID Foundation certified OpenID Provider (OP).

Ory Hydra is a certified OpenID Providier

The following OpenID profiles are certified:

To obtain certification, we deployed the reference user login and consent app (unmodified) and Ory Hydra v1.0.0.

Deployment options

You can run Ory Hydra in two main ways:

  • As a managed service on the Ory Network
  • As a self hosted service under your own control, with or without the Ory Enterprise License

Use Ory Hydra on the Ory Network

The Ory Network is the fastest way to use Ory services in production. Ory OAuth2 & OpenID Connect is powered by the open source Ory Hydra server and is API compatible.

The Ory Network provides:

  • OAuth2 and OpenID Connect for single sign on, API access, and machine to machine authorization
  • Identity and credential management that scales to billions of users and devices
  • Registration, login, and account management flows for passkeys, biometrics, social login, SSO, and multi factor authentication
  • Prebuilt login, registration, and account management pages and components
  • Low latency permission checks based on the Zanzibar model with the Ory Permission Language
  • GDPR friendly storage with data locality and compliance in mind
  • Web based Ory Console and Ory CLI for administration and operations
  • Cloud native APIs compatible with the open source servers
  • Fair, usage based pricing

Sign up for a free developer account to get started.

Self-host Ory Hydra

You can run Ory Hydra yourself for full control over infrastructure, deployment, and customization.

The install guide explains how to:

  • Install Hydra on Linux, macOS, Windows, and Docker
  • Configure databases such as PostgreSQL, MySQL, and CockroachDB
  • Deploy to Kubernetes and other orchestration systems
  • Build Hydra from source

This guide uses the open source distribution to get you started without license requirements. It is a great fit for individuals, researchers, hackers, and companies that want to experiment, prototype, or run unimportant workloads without SLAs. You get the full core engine, and you are free to inspect, extend, and build it from source.

If you run Hydra as part of a business-critical system, for example OAuth2 and OpenID Connect for all your users, you should use a commercial agreement to reduce operational and security risk. The Ory Enterprise License (OEL) layers on top of self-hosted Hydra and provides:

  • Additional enterprise features that are not available in the open source version
  • Regular security releases, including CVE patches, with service level agreements
  • Support for advanced scaling, multi-tenancy, and complex deployments
  • Premium support options with SLAs, direct access to engineers, and onboarding help
  • Access to a private Docker registry with frequent and vetted, up-to-date enterprise builds

For guaranteed CVE fixes, current enterprise builds, advanced features, and support in production, you need a valid Ory Enterprise License and access to the Ory Enterprise Docker registry. To learn more, contact the Ory team.

Quickstart

Install the Ory CLI and create a new project to try Ory OAuth2 & OpenID Connect.

# Install the Ory CLI if you do not have it yet:
bash <(curl https://raw.githubusercontent.com/ory/meta/master/install.sh) -b . ory
sudo mv ./ory /usr/local/bin/

# Sign in or sign up
ory auth

# Create a new project
ory create project --create-workspace "Ory Open Source" --name "GitHub Quickstart" --use-project

Try out the OAuth 2.0 Client Credentials flow:

ory create oauth2-client \
    --name "Client Credentials Demo" \
    --grant-type client_credentials
# Note the client ID and secret from output

ory perform client-credentials \
    --client-id <your-client-id> \
    --client-secret <your-client-secret>
# Note the access token from output

ory introspect token <your-access-token>

Try out the OAuth 2.0 Authorize Code + OpenID Connect flow:

ory create oauth2-client \
    --name "Authorize Code with OpenID Connect Demo" \
    --grant-type authorization_code,refresh_token \
    --response-type code \
    --redirect-uri http://127.0.0.1:4446/callback

ory perform authorization-code \
    --client-id <your-client-id> \
    --client-secret <your-client-secret>

Who is using Ory Hydra

The Ory community stands on the shoulders of individuals, companies, and maintainers. The Ory team thanks everyone involved - from submitting bug reports and feature requests, to contributing patches and documentation. The Ory community counts more than 50.000 members and is growing. The Ory stack protects 7.000.000.000+ API requests every day across thousands of companies. None of this would have been possible without each and everyone of you!

The following list represents companies that have accompanied us along the way and that have made outstanding contributions to our ecosystem. If you think that your company deserves a spot here, reach out to office@ory.com now!

Name Logo Website Case Study
OpenAI OpenAI
        </td>
openai.com OpenAI Case Study
Fandom Fandom
        </td>
fandom.com Fandom Case Study
Lumin Lumin
        </td>
luminpdf.com Lumin Case Study
Sencrop Sencrop
        </td>
sencrop.com Sencrop Case Study
OSINT Industries OSINT Industries
        </td>
osint.industries OSINT Industries Case Study
HGV HGV
        </td>
hgv.it HGV Case Study
Maxroll Maxroll
        </td>
maxroll.gg Maxroll Case Study
Zezam Zezam
        </td>
zezam.io Zezam Case Study
T.RowePrice T.RowePrice
        </td>
troweprice.com
Mistral Mistral
        </td>
mistral.ai
Axel Springer Axel Springer
        </td>
axelspringer.com
Hemnet Hemnet
        </td>
hemnet.se
Cisco Cisco
        </td>
cisco.com
Presidencia de la República Dominicana Presidencia de la República Dominicana
        </td>
presidencia.gob.do
Moonpig Moonpig
        </td>
moonpig.com
Booster Booster
        </td>
choosebooster.com
Zaptec Zaptec
        </td>
zaptec.com
Klarna Klarna
        </td>
klarna.com
Raspberry PI Foundation Raspberry PI Foundation
        </td>
raspberrypi.org
Tulip Tulip Retail
        </td>
tulip.com
Hootsuite Hootsuite
        </td>
hootsuite.com
Segment Segment
        </td>
segment.com
Arduino Arduino
        </td>
arduino.cc
Sainsbury's Sainsbury's
        </td>
sainsburys.co.uk
Contraste Contraste
        </td>
contraste.com
inMusic InMusic
        </td>
inmusicbrands.com
Buhta Buhta
        </td>
buhta.com
Amplitude amplitude.com
        </td>
amplitude.com
TIER IV Kyma Project Serlo Padis
Cloudbear Security Onion Solutions Factly All My Funds
Nortal OrderMyGear R2Devops Paralus
dyrector.io pinniped.dev pvotal.tech

Many thanks to all individual contributors

Ecosystem

We build Ory on several guiding principles when it comes to our architecture design:

  • Minimal dependencies
  • Runs everywhere
  • Scales without effort
  • Minimize room for human and network errors

Ory's architecture is designed to run best on a Container Orchestration system such as Kubernetes, CloudFoundry, OpenShift, and similar projects. Binaries are small (5-15MB) and available for all popular processor types (ARM, AMD64, i386) and operating systems (FreeBSD, Linux, macOS, Windows) without system dependencies (Java, Node, Ruby, libxml, ...).

Ory Kratos: Identity and User Infrastructure and Management

Ory Kratos is an API-first Identity and User Management system that is built according to cloud architecture best practices. It implements core use cases that almost every software application needs to deal with: Self-service Login and Registration, Multi-Factor Authentication (MFA/2FA), Account Recovery and Verification, Profile, and Account Management.

Ory Hydra: OAuth2 & OpenID Connect Server

Ory Hydra is an OpenID Certified™ OAuth2 and OpenID Connect Provider which easily connects to any existing identity system by writing a tiny "bridge" application. It gives absolute control over the user interface and user experience flows.

Ory Oathkeeper: Identity & Access Proxy

Ory Oathkeeper is a BeyondCorp/Zero Trust Identity & Access Proxy (IAP) with configurable authentication, authorization, and request mutation rules for your web services: Authenticate JWT, Access Tokens, API Keys, mTLS; Check if the contained subject is allowed to perform the request; Encode resulting content into custom headers (X-User-ID), JSON Web Tokens and more!

Ory Keto: Access Control Policies as a Server

Ory Keto is a policy decision point. It uses a set of access control policies, similar to AWS IAM Policies, in order to determine whether a subject (user, application, service, car, ...) is authorized to perform a certain action on a resource.

Documentation

The full Ory Hydra documentation is available at www.ory.com/docs/hydra, including:

For upgrading and changelogs, check releases tab and CHANGELOG.md.

Developing Ory Hydra

See DEVELOP.md for information on:

  • Contribution guidelines
  • Prerequisites
  • Install from source
  • Running tests
  • Build Docker image
  • Preview API documentation

Security

OAuth2 and OAuth2 related specifications are over 400 written pages. Implementing OAuth2 is easy, getting it right is hard. Ory Hydra is trusted by companies all around the world, has a vibrant community and faces millions of requests in production each day. Read the security guide for more details on cryptography and security concepts.

Disclosing vulnerabilities

If you think you found a security vulnerability, please refrain from posting it publicly on the forums, the chat, or GitHub. You can find all info for responsible disclosure in our security.txt.

Telemetry

Our services collect summarized, anonymized data that can optionally be turned off. Click here to learn more.

Libraries and third-party projects

Official:

Community:

Developer Blog:

  • Visit the Ory Blog for guides, tutorials and articles around Ory Hydra and the Ory ecosystem.

Frequently asked questions

Is hydra free to use?

hydra is open source under the Apache-2.0 licence. There is no licence fee and no seat count — you can self-host it or, where the project offers one, pay a vendor for a managed version instead.

What does hydra do?

Internet-scale OpenID Certified™ OpenID Connect and OAuth2.1 provider that integrates with your user management through headless APIs. Solve OIDC/OAuth2 user ca

What is hydra written in?

hydra is primarily written in Go. Its source is publicly available at https://github.com/ory/hydra, and it has 17,646 GitHub stars.