# Start guide
Welcome to the Aerion documentation. This guide is the best place to start: it explains what Aerion is, what you can do with it, how it fits together, and where to go next.

![](/images/guides/start-guide/image-mqrxoxpf.png)

## What is Aerion

Aerion is a work-management platform for professional-services teams — agencies, consultancies, and in-house teams who bill or budget their time. It brings **time tracking, project management, capacity planning, skills, and invoicing** together in one place, so the hours your team works flow all the way through to project budgets, staffing decisions, and client invoices.

## What you can do with Aerion

* **Track time and get it approved** — log work and project time, submit it for review, and run it through an approval flow. See [Submit work and project time](/guides/submit-work-and-project-time).
* **Run projects** — organize work by client and project, set a budget and billing type (Fixed price or Time & material), and follow health, insights, and activity. See [Clients & projects board](/guides/clients-and-projects-board).
* **Plan capacity and staff by skill** — forecast who is working on what, spot over- and under-booking, and put the right, available people on each project. See [Project planner](/guides/project-planner), [Utilization planner](/guides/utilization-planner), and [Staffing projects](/guides/staffing-projects).
* **Manage skills** — maintain a skill model for your team and use it to staff work. See [Skills overview](/guides/skills-overview).
* **Invoice and bill** — turn billable time and expenses into invoices, plan invoices in advance, and handle expenses and down payments. See [Invoice projects](/guides/invoice-projects).
* **Administer your organization** — manage login methods, teams, roles, absences, and billing. See [Login methods](/guides/login-methods).

## How it works

Work in Aerion is organized as **clients → projects (and sub-projects) → tasks**. People record **time entries** against tasks; those entries are submitted, approved, and then billed. Each project has a **budget** and a **billing type**, so tracked and planned hours roll up into profitability, planning accuracy, and remaining-budget figures you can see in project **insights** and the planners. Planning sits alongside tracking: you plan capacity ahead of time, then compare planned against tracked as the work happens, and finally invoice the billable result.

## Connect your tools

Aerion connects to the tools your team already uses so data doesn't have to be entered twice:

* **Ticketing & issues** — sync projects and issues from your ticketing tool (Jira, Asana, GitHub, GitLab, monday.com, Azure DevOps, and more), log time against them, and push entries back as worklogs. See [Jira Cloud integration](/guides/jira-cloud-integration) for an example.
* **CRM** — connect your CRM (Salesforce, HubSpot, Pipedrive, Dynamics 365, and more) to line up deals and clients with projects. See [Connect HubSpot](/guides/connect-hubspot) for an example.
* **HRIS** — sync work time with your HR system. Aerion connects to over 200 HRIS, including Personio, HRworks, BambooHR, and many more. See [Personio work time sync](/guides/personio-work-time-sync) for an example.
* **Billing & invoicing** — create invoices in your billing tool (easybill, sevDesk, and potentially DATEV) and attach timesheets automatically. See [Invoice automation with easybill](/guides/invoice-automation-with-easybill) for an example.
* **AI agents (MCP)** — connect agents to Aerion through its MCP server to read and act on your Aerion data (see the developer section below).

## About these docs

The documentation is organized by area — **Getting started, Time tracking & approval, Projects, Planning, Skills, Teams, Invoicing, Administration, and Integrations**. Each area holds focused how-to guides written around real tasks. If you're new, start here and follow the cross-links; if you're moving from the previous version, see [Migrating to Aerion 2.0](/guides/migrating-to-aerion-20).

## For developers

Aerion is built to be automated and extended — see the [developer documentation](https://docs.aerion.app/developer/) for the full picture:

* [API reference](https://docs.aerion.app/api) — a REST API for reading and writing your Aerion data (projects, time entries, analytics, and more), with full endpoint documentation.
* [MCP server](https://docs.aerion.app/developer/mcp) — a Model Context Protocol server that lets AI agents work with Aerion directly: query projects and analytics, submit time entries, and more, using the same permissions as the connected user.