> ## Documentation Index
> Fetch the complete documentation index at: https://docs.feedal.io/llms.txt
> Use this file to discover all available pages before exploring further.
# Core concepts
> The fundamental building blocks of Feedal — forms, nodes, versions, sessions, and conditions.
Understanding a handful of concepts makes the rest of Feedal click immediately. This page covers each building block, what it does, and how they connect.
## The data model
```mermaid theme={null}
graph TD
Form["Form\n(e.g. Customer Survey)"]
Draft["Draft\n(work in progress)"]
Version["Published Version\n(immutable snapshot)"]
Graph["Form Graph"]
Node["Nodes\nwelcome · question · statement · end"]
Edge["Edges\n(connections between nodes)"]
Condition["Conditions\n(branch on answers)"]
Session["Session\n(one respondent's visit)"]
Response["Node Response\n(one answer per question)"]
Form --> Draft
Form --> Version
Version --> Graph
Graph --> Node
Graph --> Edge
Edge -->|optional| Condition
Session -->|"linked to version"| Version
Session --> Response
Response -->|"linked to"| Node
```
***
## Form
A **Form** is the top-level container. It has a name, a slug (used in its public URL), and always has exactly one active **Draft** and zero or more **Published Versions**.
You manage forms from the dashboard home. Opening a form takes you into the **Studio**, where you edit its draft.
The form's public URL is `yourdomain.com/f/{slug}`. The slug is set when you
create the form and can be changed in Settings.
***
## Node
A **Node** is a single step in a form. Nodes are the building blocks you arrange in the Studio. There are four node types:
| Type | Purpose | Has outgoing edges? |
| ----------- | --------------------------------------------------- | ------------------- |
| `welcome` | Opening screen before questions start | Yes |
| `question` | Collects an answer from the respondent | Yes |
| `statement` | Informational screen, no answer required | Yes |
| `end` | Closing screen or redirect — terminates the session | No |
A form must have at least one `welcome` node (the **entry node**) and at least one `end` node (the **fallback end node**). Every other node sits between them.
Question nodes have a **question type** — short text, multiple choice, rating, and so on. See [Question types](/building-forms/questions/text) for the full list.
***
## Graph
The **Form Graph** is the complete description of a form's structure: all its nodes and all the edges connecting them. It is stored as a single JSON document and versioned atomically — when you publish, the entire graph is snapshotted.
The graph has two special pointers:
* **`entry_node_id`** — which node respondents see first
* **`fallback_end_node_id`** — where respondents land if no conditional edge matches
***
## Edge
An **Edge** is a directed connection from one node to another. Edges define the flow — they tell the engine "after this node, go to that node".
Every node can have multiple outgoing edges. Edges are evaluated in **priority order** (lowest number first). The first edge whose condition is satisfied (or which has no condition) is followed.
One outgoing edge with no condition acts as the **default route** — it always
matches and is typically placed last (highest priority number).
***
## Condition
A **Condition** is an optional rule attached to an edge. When an edge has a condition, it is only followed if the condition evaluates to `true` based on the respondent's answers.
Conditions are built from **rule groups**:
```
Condition
└── groups (evaluated with AND or OR between them)
└── rules (each rule: variable · operator · value)
```
A **variable** is typically a node ID — it refers to the answer the respondent gave to that question. Operators include `equals`, `contains`, `greater_than`, `between`, `is_answered`, `is_skipped`, and more.
See [Conditional branching](/building-forms/workflow/branching) for the full condition builder reference.
***
## Version
A **Version** is an immutable, published snapshot of the form graph. When you click **Publish**, Feedal freezes the current draft into a new version. Respondents always fill out a specific version — this means historical responses remain accurate even after you update the form.
| | Draft | Published Version |
| ---------------------- | ----------------------- | ------------------ |
| **Mutable** | Yes — edits happen here | No — never changes |
| **Respondents see it** | No (preview only) | Yes |
| **One per form** | Yes | One per publish |
| **Responses attached** | No | Yes |
Publishing does not replace the draft. After publishing, the draft continues
to exist and you can keep editing it independently.
***
## Session
A **Session** represents one respondent's visit to a published form. It is created the moment someone opens the form URL and tracks:
* Which version they are filling out
* Their current position in the graph
* The path of nodes they have visited (`traversal_path`)
* Status: `in_progress`, `completed`, or `abandoned`
* Metadata: IP address, user agent, referrer, source channel, device type, location
Sessions can be browsed and inspected individually in the [Responses](/results/responses) tab of the Results hub.
***
## Node Response
A **Node Response** (or simply a **Response**) is a single answer recorded within a session — one per question the respondent answered. It stores:
* The node it belongs to
* The answer value (type depends on the question type)
* Time spent on this question
* Score awarded (if scoring is enabled)
Screen nodes (`welcome`, `statement`, `end`) do not produce Node Responses —
only `question` nodes do.
***
## Next steps
Build and share your first form in 5 minutes.
Learn how the three-tab Studio is organized.
Explore all 18 question types.
Build logic that adapts to each respondent's answers.