---
title: "Feeds as inputs"
description: "A feed is a series published on OpenMarket under an address, @scope/name: an air quality reading every hour, a city's temperature, a daily total. An indicator…"
order: 14
section: "core-concepts"
---

<!-- source: docs/indicators/core-concepts/feeds-as-inputs.md; generated by packages/cli/scripts/gen-indicator-docs.ts, do not edit -->

# Feeds as inputs

A feed is a series published on OpenMarket under an address, `@scope/name`:
an air quality reading every hour, a city's temperature, a daily total. An
indicator reads a feed like any other source ([Data sources](data-sources.md)):
one `input` declaration, read in `onBar()` through `in_<name>()`, lined up
on the chart's own bars.

## Declaring a feed

```text
input("close", ohlcv.close);                                                  // the chart's own candles: the bars
input("aqi", series.value, { ref: "@perceptlabs/kl-aqi", missing: "carry" }); // the feed, by its address
```

| Part | What it is |
| --- | --- |
| `series.value` | The feed's reading: its first value key. |
| `ref` | The feed's address, `@scope/name`. Required. |
| `missing` | `"carry"` (the default) repeats the last reading on a bar without one; `"nan"` leaves that bar empty. |

The sheet records the input as
`{ "source": "series", "field": "value", "ref": "@perceptlabs/kl-aqi", "missing": "carry" }`.
A feed is never the first input: the chart's own candles come first and set
the bars every reading lands on.

## How readings land on bars

- A bar reads the last reading published inside it, on the chart's
  interval in UTC.
- Under `"carry"`, a bar with no reading repeats the last one, and the
  reading just before the loaded window seeds the first bars.
- Under `"nan"`, a bar with no reading reads `NaN` and draws nothing: the
  right policy for events, where a quiet bar means nothing happened.
- A feed that publishes faster than the chart's bars shows its last reading
  per bar; a slower one carries between readings, or leaves gaps under
  `"nan"`.

## Where a feed is read

| Where | What it reads |
| --- | --- |
| The chart | `@scope/name` feeds, on 1m, 5m, 15m, 30m, 1h, 4h, 1D and 1W charts |
| OpenMarket's cloud | the same feeds, for an indicator running there |
| Your OpenMarket runner | the same feeds, plus `watch/<slug>/<key>`, a series one of your watches keeps |

## Refusals

The chart names the reason before it fetches anything:

| The chart says | Because |
| --- | --- |
| feeds read on 1m, 5m, 15m, 30m, 1h, 4h, 1D and 1W charts | the chart's interval is not one feeds are read on |
| a watch series reads on your OpenMarket runner | the `ref` is a `watch/<slug>/<key>` series |
| state feeds are not numeric | the feed publishes states, not numbers |
| has no readings yet | nothing has been published to the feed so far |

## Starting points

The template picker's **Feeds** group holds three complete indicators
([The editor](../getting-started/the-editor.md)):

| Card | Reads | Draws |
| --- | --- | --- |
| Feed with an alert line (`feed-alert-line`) | `@perceptlabs/kl-aqi` | the feed as a line, an alert line at a level you set, the feed shaded above it and a mark on each cross up |
| Feed events as labeled dots (`feed-events`) | `@perceptlabs/usgs-quakes` | a faint column per reading and a labeled dot on every reading from a smallest value up |
| Feed status card (`feed-status-card`) | `@perceptlabs/nyc-temperature` | a card with the last reading, how long ago it changed and whether the feed is live, lagging or stale |

Change `ref` to read another feed; the rest of the file follows it.