Open-source alternatives to Certificates

Octelium is a zero-trust network access platform and identity-aware proxy designed to secure private HTTP, SSH, and SQL resources. It functions as a secure gateway that validates human and workload identities using OIDC, SAML, and FIDO2 passkeys before granting access to internal applications and SaaS APIs. The system is distinguished by its secretless access broker, which injects credentials—such as API keys, passwords, and AWS Sigv4 signatures—at the gateway level so users can access databases and cloud resources without managing secrets. It further specializes in AI gateway administration,

Pangolin is a zero-trust remote access platform designed to provide secure, identity-aware connectivity to private network resources. It functions as a cloud-native network controller that orchestrates encrypted tunnels, traffic routing, and access policies across distributed environments. By leveraging WireGuard for secure data transport, the platform enables authenticated access to internal web applications, terminal sessions, and remote desktops without exposing services to the public internet. The platform distinguishes itself through a declarative infrastructure model that synchronizes n

cert-manager is a Kubernetes TLS certificate manager and cluster add-on that automates the issuance and renewal of TLS certificates. It functions as a certificate lifecycle automator, managing certificates as native Kubernetes resources to secure internal and external network traffic. The project includes an ACME protocol client to automate certificate requests and validations from providers. It utilizes a controller to synchronize the desired state of certificates with responses from various certificate authorities. The system covers certificate provisioning from external issuers and vault

Tailscale is a zero-trust networking overlay that connects distributed devices and services into a private, encrypted mesh network. By utilizing a high-performance, user-space implementation of the WireGuard protocol, it establishes secure peer-to-peer tunnels across diverse network topologies without requiring complex firewall configuration. The platform operates on a centralized control plane that manages global network state, authentication, and policy distribution, ensuring that connectivity is governed by identity rather than traditional IP-based rules. What distinguishes Tailscale is it

NetBird is a zero-trust networking platform that builds secure, encrypted peer-to-peer overlay networks using the WireGuard protocol. It functions as a software-defined perimeter, connecting distributed infrastructure across cloud environments and physical locations while hiding network resources from the public internet. By integrating with external identity providers, the platform enforces granular access control and identity-based segmentation for every user and device. The platform distinguishes itself through extensive automation and programmatic management capabilities. It provides a ce

This project is a toolkit for creating and managing X.509 certificate authorities, providing tools for the issuance, signing, and management of TLS certificates and private keys. It includes a command-line utility for generating certificate signing requests, bundling certificate chains, and parsing PEM or DER files. The system features an HTTP API server that allows for remote signing and verification of certificates using JSON requests and responses. This architecture supports automated certificate provisioning and includes a signing proxy to forward requests to remote backend services. The

Allinssl is a multi-platform certificate manager and ACME automator designed to handle the full lifecycle of security certificates. It provides a web-based management interface to orchestrate the issuance, renewal, and deployment of certificates across various servers and cloud environments. The system distinguishes itself through an orchestration engine that pushes certificates to diverse targets, including web application firewalls, server control panels, and remote hosts. It automates domain ownership verification using DNS challenges across multiple providers and employs an event-driven w

This project provides a comprehensive guide and set of scripts for deploying and configuring a production-ready Kubernetes cluster from scratch. It centers on establishing a functional environment by installing core management components, storage, and networking across multiple nodes. The implementation emphasizes high availability for the control plane, utilizing layer-4 load balancing and leader election for the API server, scheduler, and controller manager. It further ensures reliability through the deployment of a distributed key-value store for persistent runtime data. The project cover

Certmagic is a Go library for automating the issuance and renewal of TLS certificates. It functions as an automatic HTTPS provisioner and ACME client that handles the full lifecycle of certificates to ensure secure connectivity without manual intervention. The library is distinguished by its support for on-demand TLS provisioning, which generates certificates dynamically during the TLS handshake based on the server name. It also provides automation for wildcard certificates through DNS challenge verification and integrates with the ZeroSSL API for certificate acquisition. The project covers

This project provides a complete OpenVPN server deployment packaged as a Docker container, with an integrated EasyRSA certificate authority for automated public-key infrastructure management. It handles the full lifecycle of a VPN server, from initial PKI bootstrap and server configuration generation to client certificate issuance and revocation, all within a containerized environment. The server is configured entirely through Docker environment variables, eliminating the need for manual configuration file editing. It supports time-based one-time password (TOTP) authentication as a second fac

Casdoor is a centralized identity and access management platform that functions as an OAuth 2.0 authorization server. It provides a comprehensive suite of services for managing user identities, authentication sessions, and access policies across both web and machine-to-machine applications. Built with a decoupled frontend-backend architecture in Go, the platform supports high-concurrency environments and offers a web-based management interface for administrative tasks. The platform distinguishes itself through its extensive support for federated identity management, allowing integration with

This project is a command-line tool that automates the entire lifecycle of security certificates using standard domain validation protocols. It functions as a background service to manage the issuance, renewal, and installation of certificates, ensuring that encrypted web traffic remains active without requiring manual intervention. The tool distinguishes itself through extensive support for automated domain ownership verification, including the ability to issue wildcard certificates by programmatically interacting with external domain name system providers. It provides flexible validation op

rustdesk-server is a self-hosted remote desktop server infrastructure designed to manage ID signaling and relay traffic for remote connections between peers. It provides the necessary backend environment to coordinate remote access sessions through rendezvous-based signaling and relay-based traffic forwarding. The system distinguishes itself with a remote access management console for organizing devices and enforcing security policies, as well as an identity integrator for OIDC-based federation and LDAP directory synchronization. It utilizes geolocation-aware routing to distribute traffic acr

Teleport is a zero-trust access platform designed to provide secure, identity-based connectivity to servers, databases, and Kubernetes clusters. It functions as a centralized gateway that replaces static credentials with short-lived, identity-bound cryptographic certificates, effectively eliminating the need for traditional VPNs and long-term secret exposure. The platform distinguishes itself by orchestrating access through a unified control plane that maps external identity provider claims to granular, role-based infrastructure permissions. It enforces security through mutual TLS gateways an

Boulder is a production-grade implementation of the ACME (Automated Certificate Management Environment) protocol, built around the same infrastructure that powers Let's Encrypt. It functions as a full certificate authority that automates the issuance, renewal, and revocation of TLS certificates, supporting multiple key algorithms including RSA, ECDSA, and experimental post-quantum ML-DSA keys. The project distinguishes itself through its multi-algorithm PKI hierarchy, which builds separate RSA and ECDSA root chains with cross-signing to support dual-algorithm trust paths. It includes a CRL-ba

Maddy is a modular mail server that assembles a complete email system by connecting small, single-purpose modules through a declarative configuration file. Rather than a monolithic stack, it lets operators compose message processing, storage, authentication, and security enforcement from interchangeable building blocks, with each module handling a specific function like receiving SMTP connections, verifying credentials, or applying policy checks. The server distinguishes itself through its flexible authentication and security architecture. It delegates user verification to external systems in

Grist is a relational spreadsheet platform that combines the flexibility of a spreadsheet with the power of a relational database. At its core, it manages structured data across multiple linked tables, using a relational database engine to organize information while providing a familiar grid interface. The platform supports Python-based formulas for complex calculations and data transformations, with automatic recalculation when referenced cells change. The system is designed for self-hosted deployment, storing data in either portable SQLite files or enterprise-grade PostgreSQL databases. It

Lego is an ACME certificate manager and lifecycle tool used to automate the request, renewal, and revocation of SSL and TLS certificates. It implements the ACME protocol to communicate with compliant certificate authorities and manages the full issuance process, including account registration and private key rollovers. The project distinguishes itself through extensive DNS automation, utilizing a provider-based abstraction to solve DNS-01 challenges across various third-party DNS providers. It supports advanced verification workflows such as CNAME-based challenge delegation, DNS zone discover

acme.sh is a shell-based certificate manager and ACME SSL certificate client. It automates the issuance, renewal, and installation of digital security certificates using a portable Unix shell script to remove dependencies on heavy runtime environments. The project specializes in automated domain ownership verification through a DNS challenge automator that integrates with provider APIs. It supports the generation of diverse certificate types, including wildcard certificates and issuance based on pre-existing certificate signing requests. The tool covers the full certificate lifecycle, includ

Nebula is a scalable, decentralized overlay networking tool designed to create secure, encrypted peer-to-peer connections between distributed hosts. By utilizing a certificate-based identity authority, it enables the construction of private communication fabrics across disparate physical infrastructures, such as multiple cloud providers or on-premises data centers, without requiring central authentication servers. The project distinguishes itself through a zero-trust architecture that enforces granular, policy-driven firewall filtering based on certificate-derived group memberships. It facili

Tinyauth is an authentication middleware service and identity provider that verifies user identities to grant system access. It operates as a standalone server or as an authentication gateway, utilizing a reverse proxy model to intercept requests and validate credentials before traffic reaches protected backend services. The project functions as an OpenID Connect provider for single sign-on experiences and an OAuth 2.0 gateway that delegates verification to external providers such as Google and GitHub. It also acts as an LDAP authentication server, allowing for centralized user management and

This project is a service mesh platform designed to manage, secure, and observe service-to-service communication within Kubernetes clusters. It functions as a control plane that orchestrates transparent sidecar proxies, which intercept and manage network traffic to provide reliable connectivity for microservices. By automating the injection of these proxies, the platform ensures that infrastructure-level policies are applied consistently across all workloads without requiring manual configuration changes. The platform distinguishes itself through its focus on zero-trust security and cross-clu

Infisical is a centralized secrets management platform designed to store, synchronize, and control access to sensitive credentials and configuration data across distributed development, staging, and production environments. It employs client-side encryption to ensure that secrets remain unreadable to the underlying storage infrastructure, while providing a hierarchical permission model to govern both user and machine access. The platform distinguishes itself through dynamic credential provisioning, which generates short-lived access tokens that are automatically revoked after use. It supports

Stalwart is a self-hosted email and collaboration infrastructure that provides an integrated mail server supporting SMTP, IMAP, POP3, and JMAP protocols. It functions as a comprehensive communication hub, combining email hosting with a collaboration server for shared calendars, contacts, and files. The system distinguishes itself through a distributed architecture that uses peer-to-peer cluster coordination to ensure high availability and fault tolerance. It features a built-in security suite that implements an S/MIME and OpenPGP email gateway alongside automated TLS certificate provisioning

Higress is an AI API gateway and cloud-native traffic manager that functions as a Kubernetes ingress controller. It provides a centralized system for routing, securing, and optimizing traffic directed toward large language models, AI agents, and microservice architectures. The project distinguishes itself through deep AI orchestration, including the ability to host and manage Model Context Protocol servers that transform REST APIs into tools for AI agents. It features specialized AI infrastructure for model request proxying, protocol translation across multiple providers, and semantic-based c

Talos is a minimal, immutable Linux distribution designed specifically for deploying and managing Kubernetes clusters. It functions as an API-driven infrastructure manager that replaces traditional shell access with a declarative gRPC interface to control operating system state and configuration. The system is distinguished by its use of a read-only root filesystem and a security-hardened kernel, which removes standard GNU utilities to reduce the attack surface. It ensures environment consistency by distributing the operating system as versioned, signed images and utilizes TPM-backed verified

ProxySU is a Windows desktop application that automates the deployment and management of proxy services on a Linux VPS. It combines single-click installation of multiple proxy protocols, including V2ray, Xray, Trojan, and Shadowsocks, with automatic SSL/TLS certificate provisioning and renewal through Let's Encrypt. The tool distinguishes itself by handling the full lifecycle of proxy server setup from a Windows environment, using SSH key-based authentication for secure, passwordless remote access. It also includes network optimization capabilities, such as activating the BBR TCP congestion c