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

# Log Quickstart

> Install Log locally and append your first events in minutes

Get an append-only event log running on your machine in under five minutes.
You will install Log, start the server, append events, and read them back
using curl.

## Install OpenData Log

Download and install the Log binary:

```bash theme={null}
curl -fsSL https://www.opendata.dev/install.sh | sh -s -- log
```

This places the `opendata-log` binary in the current directory.

## Start the server

Start Log on port 8081:

```bash theme={null}
./opendata-log --port 8081
```

No configuration file is needed — all options are passed as CLI flags. Data is
stored in `.data/` by default.

## Append records

Append three order events to the `orders` key. Keys and values are
base64-encoded in the JSON body:

```bash theme={null}
curl -X POST http://localhost:8081/api/v1/log/append \
  -H "Content-Type: application/json" \
  -d '{
    "records": [
      {
        "key": "b3JkZXJz",
        "value": "eyJpdGVtIjoid2lkZ2V0IiwicXR5IjozLCJwcmljZSI6OS45OX0="
      },
      {
        "key": "b3JkZXJz",
        "value": "eyJpdGVtIjoiZ2FkZ2V0IiwicXR5IjoxLCJwcmljZSI6MjQuOTV9"
      },
      {
        "key": "b3JkZXJz",
        "value": "eyJpdGVtIjoid2lkZ2V0IiwicXR5IjoxMCwicHJpY2UiOjkuOTl9"
      }
    ]
  }'
```

The key and values decode to:

| Base64                                                 | Plain text                                |
| ------------------------------------------------------ | ----------------------------------------- |
| `b3JkZXJz`                                             | `orders`                                  |
| `eyJpdGVtIjoid2lkZ2V0IiwicXR5IjozLCJwcmljZSI6OS45OX0=` | `{"item":"widget","qty":3,"price":9.99}`  |
| `eyJpdGVtIjoiZ2FkZ2V0IiwicXR5IjoxLCJwcmljZSI6MjQuOTV9` | `{"item":"gadget","qty":1,"price":24.95}` |
| `eyJpdGVtIjoid2lkZ2V0IiwicXR5IjoxMCwicHJpY2UiOjkuOTl9` | `{"item":"widget","qty":10,"price":9.99}` |

The server responds with the starting sequence number and how many records were
written:

```json theme={null}
{
  "status": "success",
  "recordsAppended": 3,
  "startSequence": 0
}
```

## Read records back

Scan all entries for the `orders` key:

```bash theme={null}
curl "http://localhost:8081/api/v1/log/scan?key=orders"
```

The response includes each entry's global sequence number and its base64-encoded
value:

```json theme={null}
{
  "status": "success",
  "key": "b3JkZXJz",
  "values": [
    { "sequence": 0, "value": "eyJpdGVtIjoid2lkZ2V0IiwicXR5IjozLCJwcmljZSI6OS45OX0=" },
    { "sequence": 1, "value": "eyJpdGVtIjoiZ2FkZ2V0IiwicXR5IjoxLCJwcmljZSI6MjQuOTV9" },
    { "sequence": 2, "value": "eyJpdGVtIjoid2lkZ2V0IiwicXR5IjoxMCwicHJpY2UiOjkuOTl9" }
  ]
}
```

Add `limit` to paginate through large result sets:

```bash theme={null}
curl "http://localhost:8081/api/v1/log/scan?key=orders&limit=1"
```

## Explore more endpoints

List all keys in the log:

```bash theme={null}
curl "http://localhost:8081/api/v1/log/keys"
```

List storage segments:

```bash theme={null}
curl "http://localhost:8081/api/v1/log/segments"
```

## Next steps

* Explore the full API in the **API reference** section in the sidebar.
* Learn how segments and compaction work in [Storage design](/log/storage-design).