# Append to dataset (`valek.josef/append-to-dataset`) Actor

Utility actor that allows you to build a single large dataset from individual default datasets of other actor runs.

- **URL**: https://apify.com/valek.josef/append-to-dataset.md
- **Developed by:** [Josef Válek](https://apify.com/valek.josef) (community)
- **Categories:** Developer tools, Automation, Open source
- **Stats:** 68 total users, 12 monthly users, 89.2% runs succeeded, 3 bookmarks
- **User rating**: No ratings yet

## Pricing

Pay per usage

This Actor is paid per platform usage. The Actor is free to use, and you only pay for the Apify platform usage, which gets cheaper the higher subscription plan you have.

Learn more: https://docs.apify.com/actors/running/actors-in-store.md#pay-per-usage

## What's an Apify Actor?

Actors are web data automations that power AI and operations. They run on the Apify platform to scrape websites, process data, connect APIs, and automate workflows.
In Batch mode, an Actor accepts a well-defined JSON input, performs an action which can take anything from a few seconds to a few hours,
and optionally produces a well-defined JSON output, datasets with results, or files in key-value store.
In Standby mode, an Actor provides a web server which can be used as a website, API, or an MCP server.
Actors are written with capital "A".

## How to integrate an Actor?

If asked about integration, you help developers integrate Actors into their projects.
You adapt to their stack and deliver integrations that are safe, well-documented, and production-ready.
The best way to integrate Actors is as follows.

- **AI agents and MCP clients** — the [Apify MCP server](https://docs.apify.com/integrations/mcp.md) at `https://mcp.apify.com` (remote, streamable HTTP, OAuth on first use).
- **Agentic workflows and local Actor development** — [Agent Skills](https://apify.com/.well-known/agent-skills/index.json) with the [Apify CLI](https://docs.apify.com/cli/docs.md): `npm install -g apify-cli`, then `apify login`.
- **JavaScript/TypeScript projects** — the official [JS/TS client](https://docs.apify.com/api/client/js/docs.md): `npm install apify-client`.
- **Python projects** — the official [Python client](https://docs.apify.com/api/client/python/docs.md): `pip install apify-client`.
- **Any other language** — the [REST API](https://docs.apify.com/api/v2.md).

For usage examples, see the [API](#api) section below.

For more details, see Apify documentation as [Markdown index](https://docs.apify.com/llms.txt) and [Markdown full-text](https://docs.apify.com/llms-full.txt).

# README

## Append to Dataset actor

Utility actor which allows you to append items from one dataset to another.

### Use cases

#### Incrementaly generate single large dataset from default datasets

When you have an actor that incrementaly produces new results in it's default dataset (Main Actor)
and it does not provide an option to change the dataset to push results to, you can
use this actor in Main Actor's webhook and thus create a single growing dataset with all
the default datasets combined.

In this case, the workflow is as follows:

- Create a task from this actor and just fill in the Target Dataset id (or name). The dataset does not need to exist beforehand.
- Create a webhook on the Main Actor that will run this task, and **keep the default payload** - specifically it's important
  to keep `eventData` in the payload.
- Now whenever you run the Main Actor, it's default dataset will get appended to the Target Dataset

#### One time dataset append

In some usecases you might want to do this just once - append contents of Source Dataset to Target Dataset.
In this case, just run the actor with Target and Source Dataset inputs (You'll find Source Dataset under Advanced options)

# Actor input Schema

## `datasetIdOrName` (type: `string`):

Dataset that should be appended to

## `sourceDatasetId` (type: `string`):

In one-time usecase, fill in the dataset to be appended

## `eventData` (type: `object`):

If the actor is run via webhook, eventData.actorRunId will be deterimined from webhook payload and it's default dataset will be appended

## Actor input object example

```json
{}
```

# API

You can run this Actor programmatically using our API. Below are code examples in JavaScript, Python, and CLI, as well as the OpenAPI specification and MCP server setup.

## JavaScript example

```javascript
import { ApifyClient } from 'apify-client';

// Initialize the ApifyClient with your Apify API token
// Replace the '<YOUR_API_TOKEN>' with your token
const client = new ApifyClient({
    token: '<YOUR_API_TOKEN>',
});

// Prepare Actor input
const input = {};

// Run the Actor and wait for it to finish
const run = await client.actor("valek.josef/append-to-dataset").call(input);

// Fetch and print Actor results from the run's dataset (if any)
console.log('Results from dataset');
console.log(`💾 Check your data here: https://console.apify.com/storage/datasets/${run.defaultDatasetId}`);
const { items } = await client.dataset(run.defaultDatasetId).listItems();
items.forEach((item) => {
    console.dir(item);
});

// 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/js/docs

```

## Python example

```python
from apify_client import ApifyClient

# Initialize the ApifyClient with your Apify API token
# Replace '<YOUR_API_TOKEN>' with your token.
client = ApifyClient("<YOUR_API_TOKEN>")

# Prepare the Actor input
run_input = {}

# Run the Actor and wait for it to finish
run = client.actor("valek.josef/append-to-dataset").call(run_input=run_input)

# Fetch and print Actor results from the run's dataset (if there are any)
print(f"💾 Check your data here: https://console.apify.com/storage/datasets/{run.default_dataset_id}")
for item in client.dataset(run.default_dataset_id).iterate_items():
    print(item)

# 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/python/docs/quick-start

```

## CLI example

```bash
echo '{}' |
apify call valek.josef/append-to-dataset --silent --output-dataset

```

## MCP server setup

```json
{
    "mcpServers": {
        "apify": {
            "type": "http",
            "url": "https://mcp.apify.com/?tools=fetch-actor-details,valek.josef/append-to-dataset"
        }
    }
}

```

The hosted server signs you in with OAuth on first connect, so no API token belongs in this config. Clients without OAuth support can send an `Authorization: Bearer <APIFY_API_TOKEN>` header instead, using a token from API & Integrations in Apify Console (https://console.apify.com/settings/integrations).

## OpenAPI specification

Download the OpenAPI definition: https://api.apify.com/v2/actors/0B7IM01QSSEvTpZPI/builds/jGbw1qzW7ToXS4vlJ/openapi.json