Client initiated batch Extension

Copyright © 2021 Val Lorentz <>

Unlimited redistribution and modification of this document is allowed provided that the above copyright notice and this permission notice remains intact.

This specification is a work-in-progress and may have major incompatible changes without warning.

This specification may change at any time and we do not recommend implementing it in a production environment.

Notes for implementing work-in-progress version 🔗

This is a work-in-progress specification.

All specifications depending on this specification MUST be draft specification and use only capability names prefixed by draft/

Introduction 🔗

This specification extends the batch specification to allow client-initiated BATCH commands.

This specification itself does not introduce any client-to-server batch type, but is designed as a framework for other specifications.

Motivation 🔗

Certain specifications call for clients to be able to send batched messages to servers, for instance draft/multiline

Architecture 🔗

Dependencies 🔗

This specification does not depend on the batch capability, which is used for server-initiated batches only.

This specification uses the [standard replies][] framework.

Capabilities 🔗

This specification does not introduce any capability.

Clients SHOULD NOT send BATCH commands to servers, unless they negotiated a capability that allows them to do so.

The client-to-server BATCH verb 🔗

This specification introduces client initiated batches. These use the same syntax as server initiated batches.

Once a client has opened a batch, it MUST NOT send any messages that are not part of the batch, until it is closed (with BATCH -reference-tag).

Clients MUST NOT send nested batches, i.e. clients may not send BATCH commands with a batch tag.

Errors 🔗

Servers MUST use FAIL messages from the [standard replies][] framework to notify clients of errors with client-initiated batches. The command is BATCH and the following codes are defined:

Implementation considerations 🔗

This section is non-normative.

While this version of the client-initated batch framework does not allow nested batches, future extensions may allow them. Client and server implementations may want to take this into account while designing their internal APIs.