diff --git a/.github/workflows/manual.yml b/.github/workflows/manual.yml
deleted file mode 100644
index ee9f72b..0000000
--- a/.github/workflows/manual.yml
+++ /dev/null
@@ -1,47 +0,0 @@
-name: ci
-
-on:
-  push:
-    branches:
-      - "master"
-
-env:
-  TEST_TAG: ${{ secrets.DOCKERHUB_USERNAME }}/intervaltree:test
-  LATEST_TAG: ${{ secrets.DOCKERHUB_USERNAME }}/intervaltree:latest
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      -
-        name: Checkout
-        uses: actions/checkout@v3
-      -
-        name: Login to Docker Hub
-        uses: docker/login-action@v2
-        with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
-      -
-        name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v2
-      -
-        name: Build and export to Docker
-        uses: docker/build-push-action@v4
-        with:
-          context: .
-          file: ./Dockerfile
-          load: true
-          tags: ${{ env.TEST_TAG }}
-      -
-        name: Test
-        run: docker run --rm ${{ env.TEST_TAG }}
-      -
-        name: Build and push
-        uses: docker/build-push-action@v4
-        with:
-          context: .
-          file: ./Dockerfile
-          push: true
-          tags: ${{ env.LATEST_TAG }}
-
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
new file mode 100644
index 0000000..fc7da39
--- /dev/null
+++ b/.github/workflows/tests.yml
@@ -0,0 +1,98 @@
+# This workflow will install Python dependencies, lint, and run tests in supported versions of Python.
+# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-python
+
+name: tests
+
+on:
+  push:
+    branches: [ "master", "gha" ]
+  pull_request:
+    branches: [ "master" ]
+
+permissions:
+  contents: read
+
+jobs:
+
+  pytest:
+    strategy:
+      matrix:
+        python-version: ["3.5", "3.6", "3.7", "3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14.0-alpha.5"]
+        include:
+          - python-version: "3.5"
+            os: ubuntu-20.04
+          - python-version: "3.6"
+            os: ubuntu-20.04
+          - python-version: "3.7"
+            os: ubuntu-22.04
+          - python-version: "3.8"
+            os: ubuntu-24.04
+          - python-version: "3.9"
+            os: ubuntu-24.04
+          - python-version: "3.10"
+            os: ubuntu-24.04
+          - python-version: "3.11"
+            os: ubuntu-24.04
+          - python-version: "3.12"
+            os: ubuntu-24.04
+          - python-version: "3.13"
+            os: ubuntu-24.04
+          - python-version: "3.14.0-alpha.5"
+            os: ubuntu-24.04
+    runs-on: ${{ matrix.os }}
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+      env:
+        PIP_TRUSTED_HOST: "pypi.python.org pypi.org files.pythonhosted.org"
+    - name: Display Python version
+      run: python -c "import sys; print(sys.version)"
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -r requirements/pytest.txt
+    - name: Test with pytest
+      run: |
+        coverage run -m pytest
+        coverage report -m
+
+  pytest-python27:
+    runs-on: ubuntu-latest
+    container: coatldev/six:latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Display Python version
+      run: python2 -c "import sys; print(sys.version)"
+    - name: Install dependencies
+      run: |
+        python2 -m pip install --upgrade pip
+        pip2 install -r requirements/pytest.txt
+    - name: Test with pytest
+      run: |
+        coverage2 run -m pytest
+        coverage2 report -m
+
+  flake8:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python 3.13
+      uses: actions/setup-python@v5
+      with:
+        python-version: 3.13
+    - name: Display Python verison
+      run: python -c "import sys; print(sys.version)"
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -r requirements/flake8.txt
+    - name: Lint with flake8
+      run: |
+        # stop the build if there are Python syntax errors or undefined names
+        flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+        # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
+        flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+
diff --git a/Dockerfile b/Dockerfile
deleted file mode 100644
index 1b7e32a..0000000
--- a/Dockerfile
+++ /dev/null
@@ -1,137 +0,0 @@
-# Modified by chaimleib March 2023 from
-#   https://github.com/vicamo/docker-pyenv/blob/main/alpine/Dockerfile
-#
-# Changes:
-# * customize the versions of python installed
-# * remove the dependency on github.com/momo-lab/xxenv-latest
-# * forbid failures when building python
-# * add other tools like parallel
-# * run intervaltree tests
-
-FROM alpine:latest AS base
-
-ENV PYENV_ROOT="/opt/pyenv"
-ENV PYENV_SHELL="bash"
-ENV PATH="${PYENV_ROOT}/shims:${PYENV_ROOT}/bin:$PATH"
-
-# http://bugs.python.org/issue19846
-# > At the moment, setting "LANG=C" on a Linux system *fundamentally breaks Python 3*, and that's not OK.
-ENV LANG C.UTF-8
-
-# runtime dependencies
-RUN set -eux; \
-    apk update; \
-    apk add --no-cache \
-        bash \
-        build-base \
-        bzip2 \
-        ca-certificates \
-        curl \
-        expat \
-        git \
-        libffi \
-        mpdecimal \
-        ncurses-libs \
-        openssl \
-        parallel \
-        readline \
-        sqlite-libs \
-        tk \
-        xz \
-        zlib \
-    ;
-
-RUN set -eux; \
-    curl -L https://github.com/pyenv/pyenv-installer/raw/master/bin/pyenv-installer | bash; \
-    pyenv update
-
-FROM base AS builder
-
-# runtime dependencies
-RUN set -eux; \
-    apk update; \
-    apk add --no-cache \
-        bzip2-dev \
-        libffi-dev \
-        ncurses-dev \
-        openssl-dev \
-        readline-dev \
-        sqlite-dev \
-        tk-dev \
-        xz-dev \
-        zlib-dev \
-    ;
-
-FROM builder AS build-2.7.18
-RUN set -eux; pyenv install 2.7.18; \
-  find ${PYENV_ROOT}/versions -depth \
-        \( \
-            \( -type d -a \( -name test -o -name tests -o -name idle_test \) \) \
-            -o \( -type f -a -name 'wininst-*.exe' \) \
-        \) -exec rm -rf '{}' +
-
-FROM builder AS build-3.6.15
-RUN set -eux; pyenv install 3.6.15; \
-  find ${PYENV_ROOT}/versions -depth \
-        \( \
-            \( -type d -a \( -name test -o -name tests -o -name idle_test \) \) \
-            -o \( -type f -a -name 'wininst-*.exe' \) \
-        \) -exec rm -rf '{}' +
-
-FROM builder AS build-3.7.16
-RUN set -eux; pyenv install 3.7.16; \
-  find ${PYENV_ROOT}/versions -depth \
-        \( \
-            \( -type d -a \( -name test -o -name tests -o -name idle_test \) \) \
-            -o \( -type f -a -name 'wininst-*.exe' \) \
-        \) -exec rm -rf '{}' +
-
-FROM builder AS build-3.8.16
-RUN set -eux; pyenv install 3.8.16; \
-  find ${PYENV_ROOT}/versions -depth \
-        \( \
-            \( -type d -a \( -name test -o -name tests -o -name idle_test \) \) \
-            -o \( -type f -a -name 'wininst-*.exe' \) \
-        \) -exec rm -rf '{}' +
-
-FROM builder AS build-3.9.16
-RUN set -eux; pyenv install 3.9.16; \
-  find ${PYENV_ROOT}/versions -depth \
-        \( \
-            \( -type d -a \( -name test -o -name tests -o -name idle_test \) \) \
-            -o \( -type f -a -name 'wininst-*.exe' \) \
-        \) -exec rm -rf '{}' +
-
-FROM builder AS build-3.10.10
-RUN set -eux; pyenv install 3.10.10; \
-  find ${PYENV_ROOT}/versions -depth \
-        \( \
-            \( -type d -a \( -name test -o -name tests -o -name idle_test \) \) \
-            -o \( -type f -a -name 'wininst-*.exe' \) \
-        \) -exec rm -rf '{}' +
-
-FROM builder AS build-3.11.2
-RUN set -eux; pyenv install 3.11.2; \
-  find ${PYENV_ROOT}/versions -depth \
-        \( \
-            \( -type d -a \( -name test -o -name tests -o -name idle_test \) \) \
-            -o \( -type f -a -name 'wininst-*.exe' \) \
-        \) -exec rm -rf '{}' +
-
-FROM base AS tester
-COPY --from=build-2.7.18 /opt/pyenv/versions/2.7.18 /opt/pyenv/versions/2.7.18
-COPY --from=build-3.6.15 /opt/pyenv/versions/3.6.15 /opt/pyenv/versions/3.6.15
-COPY --from=build-3.7.16 /opt/pyenv/versions/3.7.16 /opt/pyenv/versions/3.7.16
-COPY --from=build-3.8.16 /opt/pyenv/versions/3.8.16 /opt/pyenv/versions/3.8.16
-COPY --from=build-3.9.16 /opt/pyenv/versions/3.9.16 /opt/pyenv/versions/3.9.16
-COPY --from=build-3.10.10 /opt/pyenv/versions/3.10.10 /opt/pyenv/versions/3.10.10
-COPY --from=build-3.11.2 /opt/pyenv/versions/3.11.2 /opt/pyenv/versions/3.11.2
-
-RUN set -eux; \
-    pyenv rehash; \
-    pyenv versions
-
-WORKDIR /intervaltree
-COPY . .
-CMD [ "scripts/testall.sh" ]
-
diff --git a/MANIFEST.in b/MANIFEST.in
index 260c74a..40d2b19 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,2 +1,2 @@
 include README.md CHANGELOG.md LICENSE.txt
-recursive-include test *
+recursive-include test requirements
diff --git a/README.md b/README.md
index b7e24ae..985f9dc 100644
--- a/README.md
+++ b/README.md
@@ -26,7 +26,7 @@ pip install intervaltree
 Features
 --------
 
-* Supports Python 2.7 and Python 3.6+ (Tested under 2.7, and 3.6 thru 3.11)
+* Supports Python 2.7 and Python 3.5+ (Tested under 2.7, and 3.5 thru 3.14)
 * Initializing
     * blank `tree = IntervalTree()`
     * from an iterable of `Interval` objects (`tree = IntervalTree(intervals)`)
@@ -356,7 +356,7 @@ Based on
 Copyright
 ---------
 
-* [Chaim Leib Halbert][GH], 2013-2023
+* [Chaim Leib Halbert][GH], 2013-2025
 * Modifications, [Konstantin Tretyakov][Konstantin intervaltree], 2014
 
 Licensed under the [Apache License, version 2.0][Apache].
@@ -364,7 +364,7 @@ Licensed under the [Apache License, version 2.0][Apache].
 The source code for this project is at https://github.com/chaimleib/intervaltree
 
 
-[build status badge]: https://github.com/chaimleib/intervaltree/workflows/ci/badge.svg
+[build status badge]: https://github.com/chaimleib/intervaltree/workflows/tests/badge.svg
 [build status]: https://github.com/chaimleib/intervaltree/actions
 [GH]: https://github.com/chaimleib/intervaltree
 [issue tracker]: https://github.com/chaimleib/intervaltree/issues
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..db128d8
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,49 @@
+[project]
+name = "intervaltree"
+description='Editable interval tree data structure for Python 2 and 3'
+version = "3.2.0"
+authors = [
+  { name="Chaim Leib Halbert", email="chaim.leib.halbert@gmail.com" },
+  { name="Konstantin Tretyakov" },
+]
+readme = "README.md"
+requires-python = ">= 2.7.18, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
+license = "Apache-2.0"
+keywords = ['interval-tree', 'data-structure', 'intervals', 'tree']
+classifiers = [
+        'Development Status :: 5 - Production/Stable',
+        'Programming Language :: Python :: Implementation :: PyPy',
+        'Intended Audience :: Developers',
+        'Intended Audience :: Information Technology',
+        'Intended Audience :: Science/Research',
+        'Programming Language :: Python',
+        'Programming Language :: Python :: 2',
+        'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
+        'Programming Language :: Python :: 3.10',
+        'Programming Language :: Python :: 3.11',
+        'Programming Language :: Python :: 3.12',
+        'Programming Language :: Python :: 3.13',
+        'Programming Language :: Python :: 3.14',
+        'License :: OSI Approved :: Apache Software License',
+        'Topic :: Scientific/Engineering :: Artificial Intelligence',
+        'Topic :: Scientific/Engineering :: Bio-Informatics',
+        'Topic :: Scientific/Engineering :: Information Analysis',
+        'Topic :: Software Development :: Libraries',
+        'Topic :: Text Processing :: General',
+        'Topic :: Text Processing :: Linguistic',
+        'Topic :: Text Processing :: Markup',
+]
+
+[project.urls]
+Homepage = "https://github.com/chaimleib/intervaltree"
+Issues = "https://github.com/chaimleib/intervaltree/issues"
+
+[build-system]
+requires = ["setuptools >= 61.0"]
+build-backend = "setuptools.build_meta"
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..c58f7cb
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1 @@
+-r requirements/common.txt
diff --git a/requirements/common.txt b/requirements/common.txt
new file mode 100644
index 0000000..1e73a3a
--- /dev/null
+++ b/requirements/common.txt
@@ -0,0 +1 @@
+sortedcontainers==2.4.0
diff --git a/requirements/flake8.txt b/requirements/flake8.txt
new file mode 100644
index 0000000..3930480
--- /dev/null
+++ b/requirements/flake8.txt
@@ -0,0 +1 @@
+flake8
diff --git a/requirements/pytest.txt b/requirements/pytest.txt
new file mode 100644
index 0000000..5c843eb
--- /dev/null
+++ b/requirements/pytest.txt
@@ -0,0 +1,3 @@
+-r common.txt
+pytest
+pytest-cov
diff --git a/scripts/testall.sh b/scripts/testall.sh
deleted file mode 100755
index 1364729..0000000
--- a/scripts/testall.sh
+++ /dev/null
@@ -1,15 +0,0 @@
-#!/bin/bash
-# Tests using `python setup.py test` using different versions of python.
-
-this_dir="$(dirname "$0")"
-export base_dir="$(dirname "$this_dir")"
-
-set -x
-code=0
-for ver in $(pyenv versions --bare | sort -V); do
-  pyenv global "$ver"
-  python --version
-  python "$base_dir/setup.py" test || code=1
-done
-set +x
-exit "$code"
diff --git a/test/intervals.py b/test/intervals.py
index 7c2612e..1be24cb 100644
--- a/test/intervals.py
+++ b/test/intervals.py
@@ -126,10 +126,10 @@ def trepr(s):
         pprint(data, f)
 
 
-if __name__ == '__main__':
+# if __name__ == '__main__':
 #     ivs = gaps_rand()
 #     write_ivs_data('ivs3', ivs, docstring="""
 # Random integer ranges, with gaps.
 # """
 #     )
-    pprint(ivs)
+    # pprint(ivs)
diff --git a/test/optimality/optimality_test.py b/test/optimality/optimality_test.py
index eb2223d..a9faacf 100644
--- a/test/optimality/optimality_test.py
+++ b/test/optimality/optimality_test.py
@@ -25,8 +25,10 @@
 from test.optimality.optimality_test_matrix import OptimalityTestMatrix
 from test import data
 
+from intervaltree import IntervalTree
 
-matrix = OptimalityTestMatrix(verbose=1)
+
+matrix = OptimalityTestMatrix(verbose=True)
 matrix.run()