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Playgrounds

The Hgraph App includes built-in playgrounds for testing API queries against live Hedera network data. No external tools or setup required.

Available playgrounds:

GraphQL Playground​

GraphQL Playground

The GraphQL Playground is a full-featured IDE for writing, testing, and running GraphQL queries against Hedera mirror node data.

Open the playground​

  1. Go to GraphQL under API Playgrounds in the sidebar.
  2. The editor loads with an empty query panel on the left and a results panel on the right.

Write and run a query​

  1. Type your GraphQL query in the editor panel.
  2. Click the Run button in the toolbar (or use the keyboard shortcut).
  3. View the results in the right panel as formatted JSON.

Example query to get the latest transactions:

query {
  transaction(limit: 5, order_by: { consensus_timestamp: desc }) {
    consensus_timestamp
    entity_id
    type
  }
}

Use variables​

Click the Variables panel below the editor to add query variables as JSON. This is useful for parameterized queries that you want to reuse with different inputs.

Explore the schema​

The schema explorer lets you browse all available types, fields, and relationships in the Hedera mirror node schema.

  1. Click Schema in the playground navigation to open the visual schema explorer.
  2. Browse types and their fields.
  3. Click a field to see its type, description, and relationships.
  4. Use the explorer to build queries by selecting fields.

Save and load queries​

  • Click My Queries in the playground menu to view saved queries.
  • Save the current query by clicking the + button or Save at the bottom of the editor.
  • Click a saved query to load it into the editor.

Switch networks​

  1. Click the network selector in the playground toolbar (defaults to Hedera Mainnet).
  2. Select Hedera Testnet to query testnet data.
  3. Click Re-fetch to reload the schema for the selected network.

Additional features​

  • Prettify - auto-format your query for readability
  • Copy - copy the current query to your clipboard
  • Headers - add custom headers to your requests
  • Editor themes - change the editor theme via Settings > Theme
  • Subscriptions - real-time data streaming via WebSocket (available on Developer plans and above)

JSON-RPC Playground (Beta)​

JSON-RPC Playground

The JSON-RPC Playground lets you submit JSON-RPC calls to the Hedera EVM directly from the app.

Beta feature

The JSON-RPC Playground is currently in beta. A dialog will appear on first visit. Click Got it to continue.

Submit a call​

  1. Go to JSON-RPC under API Playgrounds in the sidebar.
  2. Enter a JSON-RPC method and parameters in the editor.
  3. Click the Run button.
  4. View the response in the results panel.

The playground supports standard Ethereum JSON-RPC methods for interacting with the Hedera EVM, including eth_chainId, eth_getBlockByNumber, eth_call, and more. See the JSON-RPC documentation for supported methods.

SQL Playground​

The SQL Playground allows you to write and execute SQL queries directly against Hgraph data.

Limited availability

The SQL Playground is currently available on select plans. If you don't see it in your sidebar, it may not be enabled for your account. Contact the team for access.

Features include:

  • Write and execute SQL queries
  • View query results in a table format
  • Schema introspection for available tables and columns

Troubleshooting​

If you encounter issues in the playgrounds, try these steps:

  1. Check your network selection. Make sure you're querying the correct network (Mainnet or Testnet) in the toolbar.
  2. Re-fetch the schema. If queries fail with schema errors, click Re-fetch in the playground settings to reload the latest schema.
  3. Clear local storage. Go to Settings > Clear Data in the playground menu to reset cached state.
  4. Refresh the page. If the editor is unresponsive, refresh your browser tab.
  5. Log out and back in. If issues persist, sign out and sign back in to refresh your session.

For additional help:

Tips​

  • Use the AI Data Agent alongside playgrounds. hgraph.ai can help you build queries using natural language, and you can copy the generated queries into the playground.
  • Publishable API keys work for playground queries. You don't need your Secret Key to test queries in the app.
  • Check the API documentation for query patterns. The GraphQL API docs include common queries, subscription examples, and schema references.
  • Connect AI tools to Hedera data. The Hgraph MCP Server lets you use Claude, ChatGPT, and other AI assistants to query Hedera data directly.