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The following definitions are provided to help you better understand the technical concepts related to using ngrok.

ALPN

ALPN (Application-Layer Protocol Negotiation) allows a client and server to negotiate which application protocol (like HTTP/2 or HTTP/1.1) to use over a secure connection during the TLS handshake. Learn More

CEL

CEL (Common Expression Language) is a fast, safe, and portable expression language developed by Google for evaluating expressions in configuration, policy, and runtime environments. Learn More

CRD

CustomResourceDefinitions allow users to extend the Kubernetes API by defining their own resource types. Learn More

Endpoint Pooling

When your create two ngrok endpoints with the same URL (and binding), those endpoints automatically form a “pool” and share incoming traffic. Learn More

Gateway API CRD

Gateway API CRDs (Custom Resource Definitions) are a set of standardized, extensible resources that manage networking configurations like routing, gateways, and traffic policies. Learn More

Helm

Helm is a package manager for Kubernetes that simplifies the deployment and management of applications on Kubernetes clusters. Learn More

Ingress

An ingress is an entry point into a network for traffic from outside of the network.

CIDR

Classless Inter-Domain Routing is a method used to allocate IP addresses more efficiently and route IP packets more flexibly than older class-based systems. Learn More

JIT provisioning

Just-In-Time Single Sign-On Provisioning is a user account provisioning method that automatically creates (or updates) user accounts at the time of login via Single Sign-On, rather than pre-creating all user accounts in advance. Learn More

K8s

K8s is an industry-standard abbreviation for Kubernetes. Learn More

Let’s Encrypt

Let’s Encrypt is a free, automated, and open certificate authority (CA) that provides digital certificates to enable HTTPS (SSL/TLS) for websites. Learn More

MCP

MCP (Model Context Protocol) is an open standard that allows AI models to access external data, tools, and services, and potentially use them to automate workflows. Learn More

OIDC

OpenID Connect (OIDC) is an authentication protocol that enables third-party applications to confirm a user’s identity and access basic profile details through a single sign-on (SSO) process. Learn More

OWASP

The Open Web Application Security Project is a non-profit organization dedicated to improving software security through providing resources, tools, and community support. Learn More

Reverse Proxy

Reverse proxies are an extra security layer between public traffic and your internal services. They live on servers or cloud services, and they intercept and forward traffic to upstream services. Learn More

Service User

A Service User (previously called a Bot User) is a service account that owns a set of credentials (authtokens, API keys, and SSH keys) independently of a person. This is useful for automated systems that programmatically interact with your ngrok accounts. Learn More

Shadow IT

Shadow IT refers to IT systems, software, and cloud services used by individuals within an organization without the IT department’s knowledge or approval. Learn More

SNI

SNI (Server Name Indication) is a TLS extension that allows a client to specify the hostname it is trying to connect to during the TLS handshake, enabling servers to present the correct SSL/TLS certificate for that hostname. Learn More

TCP-KeepAlive

TCP KeepAlive enables TCP connections to remain active even when no data is exchanged between the connected endpoints. Learn More

TLS Certificate

A TLS certificate (or SSL certificate) is a digital certificate that ensure your connection to a website or server is securly encrypted. Learn More

TLS Termination

TLS (Transport Layer Security) termination is the process of decrypting incoming TLS traffic at a server or load balancer before passing the unencrypted traffic to internal systems. Learn More

Traffic Policy

Traffic Policy is a configuration language that enables you to filter, match, manage and orchestrate traffic to your endpoints. For example, you can add authentication, send custom response, rate limit traffic, and more. Learn More

v2

v2 is shorthand for the second major version of the ngrok Agent. Learn More

v3

v3 is shorthand for the third major version of the ngrok Agent. Learn More

WAF

A web application firewall (WAF) is an intermediary service in the cloud or on a server that protects web services by filtering and monitoring HTTP traffic. Learn More