Convert JSON to a DynamoDB BatchWriteItem payload

About this tool

DynamoDB's BatchWriteItem API does not accept plain JSON. Every value has to be wrapped in a typed AttributeValue — strings become { "S": ... }, numbers become { "N": "..." }, booleans become { "BOOL": ... }, and so on. Hand-writing that wrapper for more than a couple of rows is tedious and error-prone.

This tool takes a normal JSON array of objects and produces the full BatchWriteItem request payload for you. Paste your rows, set the target table, choose put or delete, and copy the result into the AWS CLI (aws dynamodb batch-write-item --request-items file://payload.json), an SDK call, or a seeding script. It runs entirely in your browser — nothing is uploaded and no AWS credentials are involved.

What it converts

• string → { "S": "..." }
• number → { "N": "..." } (the exact JSON spelling is preserved, including large integers and decimals)
• true / false → { "BOOL": true | false }
• null → { "NULL": true }
• array → { "L": [ ... ] } (each element is converted recursively)
• object → { "M": { ... } } (each field is converted recursively)

For put, each object is wrapped as { "PutRequest": { "Item": ... } }. For delete, each object is wrapped as { "DeleteRequest": { "Key": ... } }, so you should include only the key attributes.

Worked example

Input array:

[
  { "id": "user#1", "name": "Ada", "age": 36, "active": true },
  { "id": "user#2", "name": "Grace", "age": 45, "active": false }
]

With table name Users and operation put, the tool returns:

{
  "RequestItems": {
    "Users": [
      {
        "PutRequest": {
          "Item": {
            "id": { "S": "user#1" },
            "name": { "S": "Ada" },
            "age": { "N": "36" },
            "active": { "BOOL": true }
          }
        }
      },
      {
        "PutRequest": {
          "Item": {
            "id": { "S": "user#2" },
            "name": { "S": "Grace" },
            "age": { "N": "45" },
            "active": { "BOOL": false }
          }
        }
      }
    ]
  }
}

Limits & edge cases

• 25 items maximum. DynamoDB accepts at most 25 write requests per BatchWriteItem call, so the tool errors above 25 items instead of emitting a payload AWS would reject. Split larger data sets into batches of 25.
• Input must be a JSON array of objects. A bare object, a scalar, or an array containing a non-object element is rejected with a clear error.
• The table name must not be empty.
• Numbers keep their exact text. Because DynamoDB stores N as a string, the original digits are preserved — a value like 12345678901234567890 is not rounded to a float.
• No key inference. For deletes, the tool trusts the object you provide as the key; it does not know your table's key schema, so include exactly the partition (and, if present, sort) key attributes.
• Empty values. DynamoDB rejects empty strings in some key positions and empty binary sets; this tool passes values through as written and does not validate against your table's constraints.

FAQ