---
title: Glossary
description: Terms used throughout the Futrou documentation and dashboard.
---

## Platform

- **Workspace** — the top-level account. Holds billing, members, and every project. See [Structure](/docs/workspaces/).
- **Project** — a grouping of services inside a workspace, typically one per application or environment. Every workspace starts with a project named `default`.
- **Service** — anything you create inside a project: a Serverlet, a Proxy, a DNS zone, a Volume, or a Cron.
- **Serverlet** — Futrou's compute unit. Runs a container image on CPU/RAM you choose, and can scale up, down, or to zero. See [Serverlet](/docs/serverlet/).
- **Instance** — one running copy of a serverlet. A serverlet can run as multiple instances at once, scaled automatically.
- **Plan** — the CPU/RAM tier a serverlet is sized by, billed per minute. See [Plans](/docs/serverlet/#plans).
- **Proxy** — routes traffic from the internet to a serverlet or other backend, over HTTP, TCP, or UDP. See [Proxy](/docs/proxy/).
- **Target** — a destination a proxy forwards traffic to; a proxy with more than one target load-balances between them.
- **Rule** — a condition-and-action pair on a proxy that matches requests and redirects, rewrites, or modifies them without touching your application.
- **DNS zone** — the set of DNS records for one domain, hosted on Futrou's nameservers. See [DNS](/docs/dns/).
- **Volume** — persistent storage attached to a serverlet that survives restarts.
- **Cron** — a scheduled job that runs on a timer.
- **Region** — where a service physically runs. **Public regions** are operated by Futrou; **private regions** are your own servers joined to your workspace.
- **Server** — a single physical or virtual machine that makes up a region. Not to be confused with "serverlet."
- **Variable** — an environment variable, set at the project level (applies to every serverlet) or the service level (applies to one serverlet, overriding a project-level variable with the same key).
- **Activity** — a logged entry in the audit trail of everything that happened in a workspace. See [Activities](/docs/activities/).
- **Member** — a user with access to a workspace, holding one of five roles (Viewer, Developer, Billing Manager, Administrator, Owner). See [Roles](/docs/members/).
- **API token** — a credential for the Futrou API and Futrou CLI, owned by either a user or a workspace. See [API Tokens](/docs/apikeys/).
- **User-owned token** — an API token tied to a person, short-lived and auto-rotated, acting with that user's own access.
- **Workspace-owned token** — a long-lived API token tied to a workspace rather than a person, meant for CI and integrations.
- **Join token** — the token used to add your own server to a workspace as a private region.
- **Credit** — the prepaid balance a workspace draws from to pay for services. See [Billing](/docs/billing/).
- **Futrou Cloud** — the managed dashboard, API, and account layer, acting as the **control plane** that configures and coordinates services. See [Futrou Cloud](/docs/cloud/).
- **Futrou Nasua** — the **orchestrator** that actually runs services in a region: starting containers, routing traffic, answering DNS. See [Futrou Nasua](/docs/nasua/).
- **Futrou CLI** — the terminal tool for managing Futrou Cloud or a standalone Futrou Nasua server. See [Futrou CLI](/docs/cli/).
- **Futrou MCP** — an implementation of the Model Context Protocol (MCP) that lets AI coding agents work with a workspace through natural language. See [Futrou MCP](/docs/mcp/).

## DNS record types

- **A** — maps a name to an IPv4 address.
- **AAAA** — maps a name to an IPv6 address.
- **CNAME** — aliases one name to another; can't be used on a zone's apex, only on subdomains.
- **ALIAS** — like CNAME, but usable on the zone apex.
- **MX** — mail servers for a domain, each with a priority (lower number = higher priority).
- **TXT** — arbitrary text, commonly used for domain verification, SPF, and DKIM.
- **NS** — delegates a name to other nameservers.
- **SRV** — locates services (host and port) for a name, with priority and weight.
- **CAA** — restricts which certificate authorities may issue TLS certificates for a domain.
- **PTR** — maps an address to a hostname (reverse DNS).
- **SOA** — zone metadata: primary nameserver, admin contact, serial number, and timing values. Created automatically and rarely edited by hand.
- **SVCB / HTTPS** — service binding records that advertise HTTP-related connection parameters (such as HTTP/3 support) directly in DNS.

See [DNS](/docs/dns/) for how these are used in a zone.

## Proxy concepts

- **Load balancing** — distributing traffic across a proxy's multiple targets.
- **Round Robin** — the default load-balancing strategy, spreading requests across targets over time.
- **Primary Failover** — a load-balancing strategy that sends all traffic to the first target, only using others if it fails.
- **Layer 4 / Layer 7** — networking layers distinguishing raw TCP/UDP passthrough (L4) from HTTP-aware reverse proxying (L7).
- **QUIC** — the transport protocol underlying HTTP/3.

See [Proxy](/docs/proxy/) for details on targets and rules.

## Technical terms

- **TTL (Time To Live)** — how long a DNS resolver may cache a record before checking for an update.
- **SNI (Server Name Indication)** — the hostname a client sends during the TLS handshake, used to route HTTPS traffic to the right proxy without decrypting it first.
- **HTTP/1.1, HTTP/2, HTTP/3** — the HTTP protocol versions Futrou's HTTP proxies support; the client and server negotiate the best one automatically.
- **OAuth2** — the standard authorization flow used to sign in to tools like Futrou CLI and Futrou MCP without typing a password into them directly.
- **SSO (Single Sign-On)** — signing in through an external identity provider (Google, Microsoft, GitHub, GitLab) instead of a Futrou password.
- **MFA / 2FA (Multi-/Two-Factor Authentication)** — a second verification step at login, beyond a password.
- **Cold start** — the delay before a scaled-to-zero serverlet can serve its first request, while an instance boots.
- **Rolling update** — replacing a serverlet's running instances with new ones (after an image, plan, or variable change) without downtime.
- **IaC (Infrastructure as Code)** — declaring services in a config file (Futrou's is `futrou.json`) instead of clicking through a dashboard.
- **BIND zone file** — the standard text format for DNS records, importable and exportable for a DNS zone.
- **Bearer token** — an API token sent in an HTTP `Authorization` header to authenticate a request.
- **CI (Continuous Integration)** — automatically building and testing code on every change, typically on every push.
- **CD (Continuous Deployment/Delivery)** — automatically deploying code once it passes CI, such as running `futrou deploy` on every push.
- **WAF (Web Application Firewall)** — a layer that inspects incoming HTTP traffic and blocks requests matching known attack patterns before they reach an application.
- **DDoS (Distributed Denial of Service)** — an attack that floods a target with traffic from many sources at once to overwhelm it and disrupt service for legitimate users.
- **LLM (Large Language Model)** — a machine learning model trained on large amounts of text, used to power AI coding agents like the ones [Futrou MCP](/docs/mcp/) connects to.
- **AI (Artificial Intelligence)** — software that performs tasks normally requiring human intelligence; in Futrou's docs, usually refers to AI coding agents interacting with the platform through [Futrou MCP](/docs/mcp/) or [Futrou CLI](/docs/cli/).
- **futrou.json** — the declarative config file describing a project's services, applied with `futrou deploy` via the [Futrou CLI](/docs/cli/).
- **Rate limit** — a cap on how many requests can be made in a given time; the Futrou API caps at 100 requests per second, returning `429 Too Many Requests` past that.
- **Pagination** — splitting a large list response across multiple pages, controlled with `page` and `limit` parameters.
- **ccTLD / gTLD** — country-code top-level domains (like `.de`, `.io`) versus generic top-level domains (like `.com`, `.dev`).