# Routing records

A route connects a source to a pipeline. Its condition decides which input records enter that pipeline. Delivery rules then choose destinations for the result.

## Every matching route runs

Routes have no first-match order. If two routes match a record, both pipelines run. A route with no condition matches every record from its source.

For example, give one route no condition to archive all records, and a second route the condition `includes(_raw, "ERROR")` to process errors. An error record runs through both pipelines. If both deliver to the same destination, that destination can receive both outputs.

## Split records between pipelines

To send each record through only one of two pipelines, make their conditions mutually exclusive:

| Pipeline | Route condition |
| --- | --- |
| Errors | `includes(_raw, "ERROR")` |
| Other records | `!includes(_raw, "ERROR")` |

Route conditions run before pipeline steps. Use the raw text or fields the source supplies. To choose destinations using parsed or calculated fields, use delivery conditions instead.

A record that matches no route is `Unmatched`; set its answer in the **Exceptions** on Routes. It blocks by default. Choose its answer deliberately; a record your routes overlook can pause the source. See [handling unmatched records](/docs/routing/exceptions#unmatched).

## Choose destinations

Delivery conditions read the pipeline's output. For example, after parsing `status` as an integer, `status >= 500` can send server errors to an error destination.

Check delivery conditions for overlap too. Smeltr can send a record to more than one destination. A null condition counts as false. Route and delivery conditions do not support array `map` or `filter` calls.

## Preview the result

Preview records that match each route, more than one route, and no route. Then check actual destination output after deployment. The [first-pipeline tutorial](/docs/first-pipeline#check) walks through connecting and verifying a route.

![Route preview for 12 storefront access records: all enter nginx-access, ten would go to es-web, and two are dropped by the pipeline.](/route-preview-light.png)

This preview accounts for all 12 sample records: Smeltr would send 10, and the pipeline drops 2. Preview does not deliver data.