HTTP headers

This page documents the HTTP headers used by the Zulip API.

Most important is that API clients authenticate to the server using HTTP Basic authentication. If you're using the official Python or JavaScript bindings, this is taken care of when you configure said bindings.

Otherwise, see the curl example on each endpoint's documentation page, which details the request format.

Documented below are additional HTTP headers and header conventions generally used by Zulip:

The User-Agent header

Clients are not required to pass a User-Agent HTTP header, but we highly recommend doing so when writing an integration. It's easy to do and it can help save time when debugging issues related to an API client.

If provided, the Zulip server will parse the User-Agent HTTP header in order to identify specific clients and integrations. This information is used by the server for logging, usage statistics, and on rare occasions, for backwards-compatibility logic to preserve support for older versions of official clients.

Official Zulip clients and integrations use a User-Agent that starts with something like ZulipMobile/20.0.103, encoding the name of the application and it's version.

Zulip's official API bindings have reasonable defaults for User-Agent. For example, the official Zulip Python bindings have a default User-Agent starting with ZulipPython/{version}, where version is the version of the library.

You can give your bot/integration its own name by passing the client parameter when initializing the Python bindings. For example, the official Zulip Nagios integration is initialized like this:

client = zulip.Client(
    config_file=opts.config, client=f"ZulipNagios/{VERSION}"

If you are working on an integration that you plan to share outside your organization, you can get help picking a good name in #integrations in the Zulip development community.

Rate-limiting response headers

To help clients avoid exceeding rate limits, Zulip sets the following HTTP headers in all API responses:

  • X-RateLimit-Remaining: The number of additional requests of this type that the client can send before exceeding its limit.
  • X-RateLimit-Limit: The limit that would be applicable to a client that had not made any recent requests of this type. This is useful for designing a client's burst behavior so as to avoid ever reaching a rate limit.
  • X-RateLimit-Reset: The time at which the client will no longer have any rate limits applied to it (and thus could do a burst of X-RateLimit-Limit requests).

Zulip's rate limiting rules are configurable, and can vary by server and over time. The default configuration currently limits:

  • Every user is limited to 200 total API requests per minute.
  • Separate, much lower limits for authentication/login attempts.

When the Zulip server has configured multiple rate limits that apply to a given request, the values returned will be for the strictest limit.