Log Quickstart

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:

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:

./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:

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:

{
  "status": "success",
  "recordsAppended": 3,
  "startSequence": 0
}

Read records back

Scan all entries for the orders key:

curl "http://localhost:8081/api/v1/log/scan?key=orders"

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

{
  "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:

curl "http://localhost:8081/api/v1/log/scan?key=orders&limit=1"

Explore more endpoints

List all keys in the log:

curl "http://localhost:8081/api/v1/log/keys"

List storage segments:

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.

Concepts

Timeseries

Log

Vector

Buffer

Install OpenData Log

Start the server

Append records

Read records back

Explore more endpoints

Next steps

​Install OpenData Log

​Start the server

​Append records

​Read records back

​Explore more endpoints

​Next steps

Install OpenData Log

Start the server

Append records

Read records back

Explore more endpoints

Next steps