> ## Documentation Index
> Fetch the complete documentation index at: https://docs.trypost.it/llms.txt
> Use this file to discover all available pages before exploring further.

# Variables and expressions

> Pass data between nodes with double-brace expressions and reusable workflow variables

Automations move data between nodes with **expressions**. Wrap a path in double braces and TryPost replaces it at run time with the real value:

```text theme={null}
Write a short post about {{ fetched.title }} and link to {{ fetched.link }}.
```

Expressions work in **any text field** of any node — prompts, webhook payloads, HTTP bodies, condition fields, and more.

## What data is in scope

This is the rule that trips people up most:

<Warning>
  A node can only use data from nodes connected **before** it (upstream). If a node isn't on the path leading into the current node, its data isn't available.
</Warning>

So a Generate node placed after a **Fetch RSS** node can use `{{ fetched.title }}`, but a node that runs *before* the fetch cannot — the data doesn't exist yet at that point in the flow.

<Tip>
  In any field, type `{{` to open an autocomplete of exactly what's in scope at that node. Known references are highlighted; unknown ones are flagged so you catch typos before running.
</Tip>

## Expression reference

Which expressions exist depends on which nodes run upstream.

### Schedule trigger

Available when the flow starts from a **Schedule** trigger.

| Expression               | Value                  |
| ------------------------ | ---------------------- |
| `{{ trigger.event }}`    | The trigger event name |
| `{{ trigger.fired_at }}` | When the trigger fired |

### Post trigger

Available when the flow starts from a **Post published** or **Post scheduled** trigger.

| Expression                        | Value                    |
| --------------------------------- | ------------------------ |
| `{{ trigger.post.id }}`           | The triggering post's ID |
| `{{ trigger.post.content }}`      | Its content              |
| `{{ trigger.post.status }}`       | Its status               |
| `{{ trigger.post.scheduled_at }}` | When it's scheduled      |
| `{{ trigger.post.published_at }}` | When it was published    |

### Fetch RSS

Available downstream of a **Fetch RSS** node.

| Expression                  | Value                 |
| --------------------------- | --------------------- |
| `{{ fetched.title }}`       | The feed item's title |
| `{{ fetched.link }}`        | Its link              |
| `{{ fetched.description }}` | Its description       |
| `{{ fetched.pubDate }}`     | Its publish date      |

### HTTP Request

Available downstream of an **HTTP Request** node. The whole JSON response is exposed as `fetched`, so you append whatever path you need:

```text theme={null}
{{ fetched.data.0.title }}
{{ fetched.user.name }}
```

| Expression              | Value                            |
| ----------------------- | -------------------------------- |
| `{{ fetched.<field> }}` | Any field from the JSON response |

### Generate

Available downstream of a **Generate** node.

| Expression                 | Value                         |
| -------------------------- | ----------------------------- |
| `{{ generated.content }}`  | The AI-generated post content |
| `{{ generated.post_url }}` | The generated post's URL      |

### Always available

These work anywhere in any flow.

| Expression                 | Value                           |
| -------------------------- | ------------------------------- |
| `{{ variables.YOUR_KEY }}` | A workflow variable (see below) |
| `{{ now }}`                | The current date and time       |

## Workflow variables

Workflow variables are **reusable values** you define once and reference anywhere with `{{ variables.KEY }}`. They're scoped to a single automation.

Use them for values you repeat across nodes or want to keep out of node fields — API keys, base URLs, account handles, a default hashtag.

<Steps>
  <Step title="Open the Variables tab">
    In the Workflow editor, switch to the **Variables** tab in the right sidebar.
  </Step>

  <Step title="Add a variable">
    Give it a **key** (letters, numbers, and underscores — e.g. `API_KEY`) and a **value**.
  </Step>

  <Step title="Reference it">
    Use `{{ variables.API_KEY }}` in any field, in any node.
  </Step>
</Steps>

<Note>
  Variable values are **stored encrypted**. They're safe for secrets like API keys.
</Note>

## See it in action

The surest way to learn what's available is to run the flow:

<Tip>
  Click **Run test** in the editor and open the result panel. Each node shows its exact **input** and **output**, so you can see precisely what every expression resolves to. See [Testing and monitoring](/knowledge-base/automations/monitoring).
</Tip>