slim-backtrader

A fork of backtrader, slimmed down and brought up to date with modern Python.

Aims of this project:

• Slim down unnecessary features
• Improve performance
• Update aged implementations

The work so far has removed every integration that depended on an abandoned package, deleted the Python 2 compatibility layer, and moved the project onto a standard PEP 621 build. See changelog.txt for the record and reports/ for the detail.

Feel free to contribute!

Installation

pip install slim-backtrader

The distribution is named slim-backtrader; the import name stays backtrader, so existing strategy code keeps working unchanged:

import backtrader as bt

Upstream owns backtrader on PyPI and a name there can never be reused, hence the different distribution name. The flip side is that this fork and upstream cannot be installed side by side — both claim the backtrader import name. Uninstall one before installing the other.

The engine has no third-party runtime dependencies. Optional features are installed as extras:

pip install "slim-backtrader[plotting]"    # matplotlib, for cerebro.plot()
pip install "slim-backtrader[pandas]"      # pandas >= 2.2, for the PandasData feed
pip install "slim-backtrader[online]"      # requests, for the Yahoo online feed
pip install "slim-backtrader[calendars]"   # pandas_market_calendars
pip install "slim-backtrader[talib]"       # TA-Lib indicator bindings

To work on the fork itself, install it editable from a clone instead:

pip install -e ".[dev]"         # the test suite and tooling

Python Compatibility

Python >= 3.13. Older interpreters are not supported: the compatibility shims that made 2.7 and early 3.x work have been removed, and the code uses zoneinfo from the standard library rather than pytz.

Features

• Data feeds
  • CSV files: the backtrader format, a fully configurable generic reader, SierraChart and MetaTrader 4 exports, and Yahoo CSV downloads
  • Yahoo Finance online (needs requests)
  • pandas DataFrames
  • Composite feeds: Chainer (concatenate) and RollOver (futures rolling)
• Data management
  • Filters: Heikin-Ashi, Renko bricks, session filtering and filling, calendar-day filling, day-step splitting
  • Multiple data feeds and strategies, multiple simultaneous timeframes
  • Integrated resampling and replaying
• Backtesting modes — step-by-step (next) or vectorised (runonce)
• Indicators — 122 built in, plus optional TA-Lib bindings and an easy path to writing your own
• Analyzers — TimeReturn, Sharpe, SQN, DrawDown, TradeAnalyzer, VWR, Calmar, PeriodStats, Transactions and more
• Broker simulation — Market, Close, Limit, Stop, StopLimit, StopTrail, StopTrailLimit, OCO and bracket orders, slippage, volume-based filling, continuous cash adjustment for futures-like instruments
• Position sizing via Sizers, and order_target_size/value/percent
• Cheat-on-close and cheat-on-open modes
• Schedulers and trading calendars
• Plotting (requires matplotlib)

Removed in 2.0.0

Interactive Brokers, VisualChart and Oanda (live trading and their data feeds), the pyfolio analyzer, and the blaze, InfluxDB and Quandl feeds. Each depended on a package that is abandoned, Python-2-only, or serves an API that no longer exists. See reports/DECISIONS.md.

Plotting is non-interactive

cerebro.plot() renders through the Agg backend and does not open a window. It returns the figures, so save them yourself:

figs = cerebro.plot(iplot=False)
figs[0][0].savefig("result.png")

Running the tests

conda env create -f environment.yml
conda activate backtrader
pip install -e ".[dev]"
pytest                       # 434 tests, ~50 s
pytest --cov                 # adds coverage, ~4 min

The suite is offline: no network, no credentials, no services. datas/ is tracked, so a fresh clone can run it immediately.

Continuous integration

.github/workflows/ci.yml runs on every push, on every pull request, and on demand. It is the gate; running pytest locally first is still the faster way to find out.

CI passed is the aggregate status; require that one in branch protection and adding a job later needs no change to the rule.

The macOS and Windows rows exist because pyproject.toml claims Operating System :: OS Independent; they are what makes that claim checkable rather than aspirational.

Documentation

• Project reports and decisions: reports/
• Original backtrader repository: https://github.com/mementum/backtrader
• Blog: Backtrader Blog
• Docs: Full Documentation — written for upstream; the removed integrations above no longer apply
• Indicators Reference: List of Built-in Indicators

Releasing

A release is one tag; CI does the rest.

$EDITOR backtrader/version.py       # __version__ = "2.2.0" - the whole change
$EDITOR changelog.txt               # UNRELEASED -> "2.2.0: 2026-08-24"
git commit -am "Release 2.2.0"
git tag -a v2.2.0 -m "slim-backtrader 2.2.0"
git push origin master v2.2.0

Pushing a vX.Y.Z tag runs .github/workflows/release.yml, which:

1. builds the sdist and wheel from a pristine checkout — no editable install has run there, so nothing local can leak into the artefacts;
2. stops if the tag and __version__ disagree;
3. runs twine check --strict;
4. installs the sdist on 3.13 and 3.14 and runs the suite the sdist itself ships, then installs the wheel into an empty environment and checks that it pulls in no dependencies, that import backtrader reports the right version, and that btrun --help works;
5. publishes to PyPI, and only then;
6. creates the GitHub release, with the artefacts attached and that version's changelog.txt section as the notes.

Nothing is uploaded until every step above has passed.

There is no PyPI API token in this repository. Publishing uses PyPI's trusted publishing: GitHub mints a short-lived OIDC credential, and PyPI accepts it only for this workflow file, in this repository, running in the pypi environment.

One-time setup on PyPI

At https://pypi.org/manage/project/slim-backtrader/settings/publishing/, add a GitHub publisher:

Then revoke the account-scoped API token that uploaded 2.0.0–2.1.0: it is no longer needed, and an account-scoped token is the widest credential PyPI issues.

Optionally add a required reviewer to the pypi environment in the repository's settings, which turns the upload into an approval click.

To rehearse on TestPyPI, add a pending publisher at https://test.pypi.org/manage/account/publishing/ with the same fields, the project name slim-backtrader and the environment name testpypi, then run the Release workflow manually with the TestPyPI box ticked. TestPyPI accounts are separate from PyPI ones.

Notes that save a wasted upload

• A version can only be uploaded once. PyPI rejects a re-upload of the same version even after a delete, so a correction is a new version: bump __version__ and tag again. 2.0.0, 2.0.1, 2.1.0 and 2.2.0 are spent.
• The tag is the trigger. Pushing v2.2.0 publishes 2.2.0. There is no other confirmation step unless the pypi environment has a reviewer.
• The simple index lags an upload by a few minutes. pip install reporting "no matching distribution" straight after a release is a stale CDN edge, not a failed upload. curl -s -H "Accept: application/vnd.pypi.simple.v1+json" https://pypi.org/simple/slim-backtrader/ is the check that agrees with pip once the edge expires.
• Manual fallback, if Actions is unavailable: rm -rf dist build && python -m build && twine check --strict dist/* && twine upload dist/*, with a PyPI API token as username __token__. It skips every verification above, so use it only when the workflow cannot run at all.

Version Numbering

Plain semantic versioning, X.Y.Z, starting at 2.0.0:

• X: Major version — incompatible API changes. Removing features is the point of this fork, so expect these.
• Y: Minor version — new functionality, backwards compatible.
• Z: Patch — bug fixes and documentation.

Upstream backtrader used a fourth digit for the number of built-in indicators (1.9.78.123). That digit is retired as of 2.0.0, and __btversion__ is now a 3-tuple.

License and attribution

slim-backtrader is a modified version of backtrader, originally written by Daniel Rodriguez. All of the engine's design and the overwhelming majority of its code are his work; this fork subtracts from it and modernizes it rather than replacing it.

• Copyright © 2015–2023 Daniel Rodriguez (original work)
• Copyright © 2026 Dennis Hansen (modifications)

Licensed under the GNU General Public License, version 3 or later, the same licence as upstream. The full text ships with the package in LICENSE; if you did not receive it, see https://www.gnu.org/licenses/.

This program comes with ABSOLUTELY NO WARRANTY. It is free software, and you are welcome to redistribute it under the conditions of the GPL.

Every source file modified by this fork says so in its header, with the year, as GPL-3.0 section 5(a) requires. What was changed is recorded in changelog.txt — the 2.0.0 entry lists the removed integrations, the dropped Python 2 layer and every API break.

One file is not under the GPL: backtrader/plot/multicursor.py is derived from matplotlib 1.2.0 and carries its own licence from John D. Hunter (Copyright © 2002–2011), reproduced in full at the top of that file, along with a summary of the changes made to it. It is GPL-compatible, which is why it can be distributed as part of this work.