v3.0.0

What's Changed

API improvements

• Added CustomerIO.batch() support for the Track API v2 batch endpoint in #123
• Added event deduplication support for track() and track_anonymous() via optional top-level id and timestamp fields in #125
• Track API methods now return requests.Response objects so callers can inspect status codes, headers, and response details in #122
• Added close() and context manager support for CustomerIO and APIClient to cleanly close sessions in #121
• Fixed the transactional request keyword spelling to disable_css_preprocessing in #117

Breaking Changes

• Python 3.10+ is now required. Packaging metadata and CI now target Python 3.10 through 3.14.
• track() and track_anonymous() now take custom event attributes in a data dict instead of arbitrary keyword arguments.
  • Before: cio.track(5, "purchase", type="socks", price="13.99")
  • After: cio.track(5, "purchase", {"type": "socks", "price": "13.99"})
• Track API methods now return requests.Response objects instead of None. Existing fire-and-forget calls are unaffected, but code that checks for None return values may need updating.
• ClientBase.send_request() now returns the full requests.Response instead of response.text.
• The misspelled disable_css_preproceessing transactional email argument was removed. Use disable_css_preprocessing.

Reliability and networking

• Fixed retry behavior for POST requests, including retries for transient 5xx responses, clean 4xx error handling, and support for all 2xx success responses in #119
• Fixed no-pooling session isolation so use_connection_pooling=False creates and closes a fresh session per request in #118
• Fixed a possible AttributeError during session cleanup by @bpeterman in #109
• Added TCP keepalive socket options for outbound HTTPS connections in #124

Packaging, CI, and release automation

• Modernized packaging with pyproject.toml, PEP 621 metadata, updated dependency constraints, Ruff tooling, and a Python 3.10-3.14 CI matrix in #116
• Added automated PyPI publishing for GitHub releases using trusted publishing in #120
• Removed tests from distributed packages by @louison in #99
• Updated Makefile and CI workflow configuration in #115
• Bumped the package version to 3.0.0 in #126

Documentation

• Clarified the transactional email example to show identifiers using an email address by @glosier in #97

Contributors

Thanks to everyone who contributed code, reports, investigation, or earlier PR work that shaped this release:

• @louison, first-time contributor in #99
• @bpeterman, first-time contributor in #109
• @rollerbrick, whose no-pooling session isolation work from #94 informed #118
• @joandvgv, whose event deduplication PR #98 informed #125
• @skion, for identifying the POST retry root cause in #76

Full Changelog: v2.4.0...v3.0.0