---
# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: Apache-2.0
title: "dynamo.nixl_connect.RdmaMetadata"
---

A Pydantic type intended to provide JSON serialized NIXL metadata about a [`ReadableOperation`](readable-operation.md) or [`WritableOperation`](writable-operation.md) object.
NIXL metadata contains detailed information about a worker process and how to access memory regions registered with the corresponding agent.
This data is required to perform data transfers using the NIXL-based I/O subsystem.

<Warning>
NIXL metadata contains information to connect corresponding backends across agents, as well as identification keys to access specific registered memory regions.
This data provides direct memory access between workers, and should be considered sensitive and therefore handled accordingly.
</Warning>

Use the respective class's `.metadata()` method to generate an `RdmaMetadata` object for an operation.

<Tip>
Classes using `RdmaMetadata` objects must be paired correctly.
[`ReadableOperation`](readable-operation.md) with [`ReadOperation`](read-operation.md), and
[`WritableOperation`](write-operation.md) with [`WriteOperation`](write-operation.md).
Incorrect pairing will result in an error being raised.
</Tip>


## Related Classes

  - [Connector](connector.md)
  - [Descriptor](descriptor.md)
  - [Device](device.md)
  - [OperationStatus](operation-status.md)
  - [ReadOperation](read-operation.md)
  - [ReadableOperation](readable-operation.md)
  - [WritableOperation](writable-operation.md)
  - [WriteOperation](write-operation.md)
