Install — Sverlo v2.1

Node.js versions

Sverlo 2.x runs on Node.js 20 and newer. The 1.x branch supports Node.js 14 and up but only receives security fixes.

The library#

bash

npm install sverlo

The package is plain JavaScript with type definitions: no native modules and no compiler. After installing, check that the version is what you expect:

bash

node -e "import('sverlo').then(m => console.log(m.version))"

Use import { createParser } from 'sverlo' in ESM. From CommonJS, version 2 needs a dynamic import(); there is no synchronous require, the reason is in the migration guide.

Command line#

The sverlo command is installed together with the package. A global install is only needed when you run it outside a project:

bash

npm install --global sverlo
sverlo --version

One-off run without installing:

bash

npx sverlo parse access.log --format nginx-combined --limit 5

All flags are listed in the CLI reference.

Check it works#

Create a file sample.log and parse it:

log

2026-10-01T09:14:07Z ERROR db: connection reset by peer attempt=3
2026-10-01T09:14:08Z INFO db: reconnected attempt=4

bash

sverlo parse sample.log --pattern "{ts:iso} {level:level} {msg:rest}" --out json

Two JSON objects mean the installation works. Next: the quick start.