# Variables and Tokens

> Tokens such as {{caller}}, {{digits}}, {{menu_choice}}, {{answer.key}} and {{var.name}} fill per-call data into IVR Studio prompts, HTTP requests and emails.

Source: https://edesy.in/docs/ivr/variables-and-tokens

Tokens are placeholders written as `{{name}}` that IVR Studio fills in during a call: the caller's number, the key just pressed, the menu option chosen, a spoken answer, or a variable you passed when starting the call. Prompts accept `{{var.*}}` tokens; HTTP Request and Email nodes accept every token. Variables come from the outbound API or a test call.

## All tokens

| Token | Value |
|---|---|
| `{{caller}}` | The caller's number (on an outbound call, the number dialled) |
| `{{did}}` | The other number on the call (your IVR number on an inbound call) |
| `{{digits}}` | The key just pressed in a Menu, e.g. `2` |
| `{{menu_choice}}` | The label of that menu option, e.g. `Support` |
| `{{answer.<question key>}}` | A spoken answer captured by an [Ask](https://edesy.in/docs/ivr/nodes/ask) node, e.g. `{{answer.city}}` |
| `{{var.<name>}}` | A per-call variable, e.g. `{{var.order_id}}` |
| `{{voicemail_url}}` | Link to the voicemail recorded on this call |
| `{{reference_id}}` | Your `reference_id` from the outbound API |
| `{{call_sid}}` | The call's ID |
| `{{flow_id}}` | The flow's ID |
| `{{time}}` | Now, in IST, readable |
| `{{time_iso}}` | Now, in UTC, RFC 3339 |

## Where tokens work

| Place | Tokens allowed |
|---|---|
| Say text, Menu prompt, Ask question | `{{var.<name>}}` only |
| HTTP Request URL (path and query), header values, body | All tokens |
| Email subject and message | All tokens |
| Order Action tag and note | Tokens allowed |

A `{{var.*}}` the call doesn't have is spoken as nothing. In an HTTP request or email, an unknown token is sent unchanged, so typos are easy to spot.

## Passing variables

Variables come from:

- the `variables` object of [`POST /v1/ivr/calls`](https://edesy.in/docs/ivr/api/outbound-ivr-calls);
- the **Variables (JSON, optional)** box of a [test call](https://edesy.in/docs/ivr/getting-started/test-and-publish);
- an order automation, which fills [order variables](https://edesy.in/docs/ivr/nodes/order-action#order-variables) such as `customer_name` and `cod_amount`.

```json
{ "variables": { "order_id": "A123", "name": "Ravi", "amount": 499 } }
```

## Variable limits

| Limit | Value |
|---|---|
| Variables per call | 20 |
| Name | Letters, digits and `_`, starting with a letter or `_`, up to 64 characters (`[a-zA-Z_][a-zA-Z0-9_]{0,63}`) |
| Value | String, number or boolean (stored as a string), up to 512 characters. Objects and arrays are rejected |
| Total size | 4 KB |

## Safe substitution

In HTTP requests, token values are escaped for where they land. A value can't break out of a JSON string, add a query parameter, add a header line or change the host. For JSON bodies, put tokens inside string values: `{"order_id": "{{var.order_id}}"}`.

## Variables in logs

Each call's variables are shown in [Call Logs](https://edesy.in/docs/ivr/logs/call-logs) and returned by `GET /v1/ivr/calls/{call_sid}` and the status callback.