diff --git a/.circleci/config.yml b/.circleci/config.yml
deleted file mode 100644
index a31404a..0000000
--- a/.circleci/config.yml
+++ /dev/null
@@ -1,37 +0,0 @@
-version: 2
-jobs:
-    build-and-test:
-        docker:
-            - image: continuumio/miniconda3
-        steps:
-          - checkout
-          - run:
-              name: Create conda environment
-              command: |
-                  apt-get update --yes
-                  apt-get install --yes build-essential
-                  conda env create -f environment.yml
-          - run:
-              name: Build the code
-              command: |
-                  source activate mess-env
-                  bash build.sh
-          - run:
-              name: Test the code
-              command: |
-                  source activate mess-env
-                  . debug/fake-install.sh
-                  cd examples/
-                  mess mess.inp
-                  cat mess.out
-                  messpf messpf.inp
-                  cat messpf.dat
-                  messabs messabs.inp
-                  cat messabs.out
-                  messsym messsym.inp
-                  cd ..
-workflows:
-    version: 2
-    build-all:
-        jobs:
-            - build-and-test
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..887a2c1
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,2 @@
+# SCM syntax highlighting & preventing 3-way merges
+pixi.lock merge=binary linguist-language=YAML linguist-generated=true
diff --git a/.github/workflows/static-build.yml b/.github/workflows/static-build.yml
new file mode 100644
index 0000000..a42d84d
--- /dev/null
+++ b/.github/workflows/static-build.yml
@@ -0,0 +1,30 @@
+name: Build and Upload MESS-Static
+
+on: 
+  push:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout the code
+        uses: actions/checkout@v4
+
+      - name: Set up Pixi
+        uses: prefix-dev/setup-pixi@v0.8.9
+        with:
+          manifest-path: static/pixi.toml
+
+      # Build
+      - name: Build
+        run: pixi build
+        working-directory: static/
+
+      # Upload
+      - name: Upload
+        if: ${{ github.ref == 'refs/heads/main' && github.repository == 'Auto-Mech/mechtools'}}
+        run: pixi run upload
+        env:
+          ANACONDA_API_KEY: ${{ secrets.ANACONDA_API_KEY }}
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index c8306e5..a68f47b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -56,3 +56,11 @@ debug
 
 # Ignore rattler build output folder
 output/
+
+# pixi environments
+.pixi/
+!.pixi/config.toml
+
+# Other
+test-examples/
+*.conda
diff --git a/build.sh b/build.sh
deleted file mode 100644
index 267b1f1..0000000
--- a/build.sh
+++ /dev/null
@@ -1,19 +0,0 @@
-#!/usr/bin/env bash
-
-mkdir -p build
-cd build
-
-echo $PREFIX
-
-export CFLAGS="${CFLAGS} -I${CONDA_PREFIX}/include"
-export CXXFLAGS="${CXXFLAGS} -I${CONDA_PREFIX}/include"
-# Build with MPACK
-# export CXXFLAGS="${CXXFLAGS} -I${CONDA_PREFIX}/include -I${CONDA_PREFIX}/include/mpack -DWITH_MPACK"
-
-cmake .. -DCMAKE_INSTALL_PREFIX=$PREFIX -DCMAKE_C_COMPILER=$CC -DCMAKE_CXX_COMPILER=$CXX
-
-make VERBOSE=1
-make install
-ln -s $PREFIX/bin/messpf $PREFIX/bin/partition_function
-ln -s $PREFIX/bin/messabs $PREFIX/bin/abstraction
-ln -s $PREFIX/bin/messsym $PREFIX/bin/symmetry_number
diff --git a/debug/build.sh b/debug/build.sh
deleted file mode 100644
index 0b8718d..0000000
--- a/debug/build.sh
+++ /dev/null
@@ -1,20 +0,0 @@
-#!/usr/bin/env bash
-
-export THIS_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
-export PROJECT_ROOT=$THIS_DIR/..
-
-export CC=$CONDA_PREFIX/bin/x86_64-conda_cos6-linux-gnu-gcc
-export CXX=$CONDA_PREFIX/bin/x86_64-conda_cos6-linux-gnu-c++
-
-export CFLAGS="-march=nocona -mtune=haswell -ftree-vectorize -fPIC -fstack-protector-all -fno-plt -Og -g -Wall -Wextra -fvar-tracking-assignments -ffunction-sections -pipe -I${CONDA_PREFIX}/include"
-export CXXFLAGS="-fvisibility-inlines-hidden -std=c++17 -fmessage-length=0 -march=nocona -mtune=haswell -ftree-vectorize -fPIC -fstack-protector-all -fno-plt -Og -g -Wall -Wextra -fvar-tracking-assignments -ffunction-sections -pipe -I${CONDA_PREFIX}/include"
-
-mkdir -p $THIS_DIR/build
-cd $THIS_DIR/build
-
-cmake $PROJECT_ROOT -DCMAKE_INSTALL_PREFIX=$THIS_DIR -DCMAKE_C_COMPILER=$CC -DCMAKE_C_FLAGS="${CFLAGS}" -DCMAKE_CXX_COMPILER=$CXX -DCMAKE_CXX_FLAGS="${CXXFLAGS}"
-make VERBOSE=1
-make install
-ln -s $THIS_DIR/bin/messpf $THIS_DIR/bin/partition_function
-ln -s $THIS_DIR/bin/messabs $THIS_DIR/bin/abstraction
-ln -s $THIS_DIR/bin/messsym $THIS_DIR/bin/symmetry_number
diff --git a/debug/fake-install.sh b/debug/fake-install.sh
deleted file mode 100644
index 3424a1f..0000000
--- a/debug/fake-install.sh
+++ /dev/null
@@ -1,5 +0,0 @@
-# run with: . /path/to/fake-install.sh
-export THIS_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
-export PROJECT_ROOT=$THIS_DIR/..
-
-export PATH=$THIS_DIR/bin:$PATH
diff --git a/debug/install-conda.sh b/debug/install-conda.sh
deleted file mode 100644
index 2993f35..0000000
--- a/debug/install-conda.sh
+++ /dev/null
@@ -1,10 +0,0 @@
-#!/usr/bin/env bash
-
-if [ "$(uname)" == "Darwin" ]; then
-    wget https://repo.continuum.io/miniconda/Miniconda3-latest-MacOSX-x86_64.sh
-    bash Miniconda3-latest-MacOSX-x86_64.sh -b -p $CONDA
-elif [ "$(uname)" == "Linux" ]; then
-    wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh
-    bash Miniconda3-latest-Linux-x86_64.sh -b -p $CONDA
-fi
-conda update conda
diff --git a/static/CONDA_BUILD.md b/static/CONDA_BUILD.md
deleted file mode 100644
index c83d516..0000000
--- a/static/CONDA_BUILD.md
+++ /dev/null
@@ -1,67 +0,0 @@
-# Instructions for building & uploading the conda package
-
-The following steps use the `rattler-build` and `anaconda-client` packages to
-create a conda package for installing the static MESS executables. See
-instructions below for how to install them. Once the package is built and
-uploaded, it can be installed in an environment as follows.
-```
-conda install -c auto-mech mess-static
-```
-
-### Build the conda package
-
-1. Update the version number in `static/recipe.yaml` with today's date: `YYYY.MM.DD`.
-2. Run `rattler-build build -r static/` and look for `/path/to/file.conda` in the output. Copy that path for the steps below.
-
-### Upload the conda package
-
-1. Navigate to `https://anaconda.org/` to create an API token for yourself. Save it in a secure location where you can access it.
-2. `export ANACONDA_OWNER=<username>`
-3. `export ANACONDA_API_KEY=<API token>`
-4. `anaconda upload -u auto-mech --label main /path/to/file.conda`
-
-## Testing
-
-### Testing the build
-
-To test that the build works, you can create a test environment with it installed as follows.
-```
-conda create -n test-mess /path/to/file.conda
-```
-You can then test that the conda package works as follows.
-```
-conda activate test-mess
-cd examples/
-mess mess.inp
-messpf messpf.inp
-```
-On subsequent tests, you will need to do remove the environment and clear the
-cache before re-running the above commands (note that the cache must be cleared *after* removing the test environment).
-```
-conda env remove -n test-mess
-conda clean --all   # Remove the cached version of test-mess
-```
-
-### Testing the upload
-
-Follow the same steps as shown above for testing the build, but create the
-environment using the uploaded version as follows. Don't forget to remove the
-`test-mess` environment and run `conda clean --all` if it was already created.
-```
-conda create -n test-mess -c auto-mech mess-static
-```
-
-## Dependencies
-
-The following steps use the `rattler-build` and `anaconda-client` packages.
-
-These can be installed through pixi as follows:
-```
-curl -fsSL https://pixi.sh/install.sh | bash   # installs pixi
-pixi global install rattler-build anaconda-client
-```
-
-Or, if you prefer, they can also be installed through conda:
-```
-conda install -c conda-forge rattler-build anaconda-client
-```
\ No newline at end of file
diff --git a/static/README.md b/static/README.md
new file mode 100644
index 0000000..e7f9161
--- /dev/null
+++ b/static/README.md
@@ -0,0 +1,23 @@
+# Instructions
+
+These instructions show how to build and upload the `mess-static` conda package,
+containing the static executables in this directory.
+The process relies in the Pixi package manager, which can be installed as follows.
+```
+curl -fsSL https://pixi.sh/install.sh | sh
+```
+
+### Build
+
+Build the conda package:
+```
+pixi build
+```
+
+### Upload
+
+Upload the conda package:
+```
+export ANACONDA_API_KEY=<API token>
+pixi run upload
+```
diff --git a/static/pixi.lock b/static/pixi.lock
new file mode 100644
index 0000000..79b4445
--- /dev/null
+++ b/static/pixi.lock
@@ -0,0 +1,227 @@
+version: 6
+environments:
+  default:
+    channels:
+    - url: https://prefix.dev/conda-forge/
+    packages:
+      linux-64:
+      - conda: .
+      osx-64:
+      - conda: .
+      osx-arm64:
+      - conda: .
+      win-64:
+      - conda: .
+  dev:
+    channels:
+    - url: https://prefix.dev/conda-forge/
+    packages:
+      linux-64:
+      - conda: https://prefix.dev/conda-forge/linux-64/_libgcc_mutex-0.1-conda_forge.tar.bz2
+      - conda: https://prefix.dev/conda-forge/linux-64/_openmp_mutex-4.5-2_gnu.tar.bz2
+      - conda: https://prefix.dev/conda-forge/noarch/ca-certificates-2025.8.3-hbd8a1cb_0.conda
+      - conda: https://prefix.dev/conda-forge/linux-64/libgcc-15.1.0-h767d61c_5.conda
+      - conda: https://prefix.dev/conda-forge/linux-64/libgomp-15.1.0-h767d61c_5.conda
+      - conda: https://prefix.dev/conda-forge/linux-64/libstdcxx-15.1.0-h8f9b012_5.conda
+      - conda: https://prefix.dev/conda-forge/linux-64/openssl-3.5.3-h26f9b46_1.conda
+      - conda: https://prefix.dev/conda-forge/linux-64/patchelf-0.18.0-h3f2d84a_2.conda
+      - conda: https://prefix.dev/conda-forge/linux-64/rattler-build-0.47.0-h60886be_0.conda
+      - conda: .
+      osx-64:
+      - conda: https://prefix.dev/conda-forge/osx-64/rattler-build-0.47.0-h9113d71_0.conda
+      - conda: .
+      osx-arm64:
+      - conda: https://prefix.dev/conda-forge/osx-arm64/rattler-build-0.47.0-h8d80559_0.conda
+      - conda: .
+      win-64:
+      - conda: https://prefix.dev/conda-forge/win-64/rattler-build-0.47.0-h18a1a76_0.conda
+      - conda: https://prefix.dev/conda-forge/win-64/ucrt-10.0.26100.0-h57928b3_0.conda
+      - conda: https://prefix.dev/conda-forge/win-64/vc-14.3-h41ae7f8_31.conda
+      - conda: https://prefix.dev/conda-forge/win-64/vc14_runtime-14.44.35208-h818238b_31.conda
+      - conda: https://prefix.dev/conda-forge/win-64/vcomp14-14.44.35208-h818238b_31.conda
+      - conda: .
+packages:
+- conda: https://prefix.dev/conda-forge/linux-64/_libgcc_mutex-0.1-conda_forge.tar.bz2
+  sha256: fe51de6107f9edc7aa4f786a70f4a883943bc9d39b3bb7307c04c41410990726
+  md5: d7c89558ba9fa0495403155b64376d81
+  license: None
+  size: 2562
+  timestamp: 1578324546067
+- conda: https://prefix.dev/conda-forge/linux-64/_openmp_mutex-4.5-2_gnu.tar.bz2
+  build_number: 16
+  sha256: fbe2c5e56a653bebb982eda4876a9178aedfc2b545f25d0ce9c4c0b508253d22
+  md5: 73aaf86a425cc6e73fcf236a5a46396d
+  depends:
+  - _libgcc_mutex 0.1 conda_forge
+  - libgomp >=7.5.0
+  constrains:
+  - openmp_impl 9999
+  license: BSD-3-Clause
+  license_family: BSD
+  size: 23621
+  timestamp: 1650670423406
+- conda: https://prefix.dev/conda-forge/noarch/ca-certificates-2025.8.3-hbd8a1cb_0.conda
+  sha256: 837b795a2bb39b75694ba910c13c15fa4998d4bb2a622c214a6a5174b2ae53d1
+  md5: 74784ee3d225fc3dca89edb635b4e5cc
+  depends:
+  - __unix
+  license: ISC
+  size: 154402
+  timestamp: 1754210968730
+- conda: https://prefix.dev/conda-forge/linux-64/libgcc-15.1.0-h767d61c_5.conda
+  sha256: 0caed73aac3966bfbf5710e06c728a24c6c138605121a3dacb2e03440e8baa6a
+  md5: 264fbfba7fb20acf3b29cde153e345ce
+  depends:
+  - __glibc >=2.17,<3.0.a0
+  - _openmp_mutex >=4.5
+  constrains:
+  - libgomp 15.1.0 h767d61c_5
+  - libgcc-ng ==15.1.0=*_5
+  license: GPL-3.0-only WITH GCC-exception-3.1
+  license_family: GPL
+  size: 824191
+  timestamp: 1757042543820
+- conda: https://prefix.dev/conda-forge/linux-64/libgomp-15.1.0-h767d61c_5.conda
+  sha256: 125051d51a8c04694d0830f6343af78b556dd88cc249dfec5a97703ebfb1832d
+  md5: dcd5ff1940cd38f6df777cac86819d60
+  depends:
+  - __glibc >=2.17,<3.0.a0
+  license: GPL-3.0-only WITH GCC-exception-3.1
+  license_family: GPL
+  size: 447215
+  timestamp: 1757042483384
+- conda: https://prefix.dev/conda-forge/linux-64/libstdcxx-15.1.0-h8f9b012_5.conda
+  sha256: 0f5f61cab229b6043541c13538d75ce11bd96fb2db76f94ecf81997b1fde6408
+  md5: 4e02a49aaa9d5190cb630fa43528fbe6
+  depends:
+  - __glibc >=2.17,<3.0.a0
+  - libgcc 15.1.0 h767d61c_5
+  license: GPL-3.0-only WITH GCC-exception-3.1
+  license_family: GPL
+  size: 3896432
+  timestamp: 1757042571458
+- conda: .
+  name: mess-static
+  version: 2025.9.0
+  build: h4616a5c_0
+  subdir: noarch
+  input:
+    hash: 8b79e5a3bc55d53830f91092ff4bcc7c5185097232b1ad65b0316fa5a0d921ca
+    globs:
+    - recipe.yaml
+    - variants.yaml
+- conda: https://prefix.dev/conda-forge/linux-64/openssl-3.5.3-h26f9b46_1.conda
+  sha256: 0572be1b7d3c4f4c288bb8ab1cb6007b5b8b9523985b34b862b5222dea3c45f5
+  md5: 4fc6c4c88da64c0219c0c6c0408cedd4
+  depends:
+  - __glibc >=2.17,<3.0.a0
+  - ca-certificates
+  - libgcc >=14
+  license: Apache-2.0
+  license_family: Apache
+  size: 3128517
+  timestamp: 1758597915858
+- conda: https://prefix.dev/conda-forge/linux-64/patchelf-0.18.0-h3f2d84a_2.conda
+  sha256: 2f1caf273c7816fcff6e8438138c29d08264f8371dc0e23f86e993ccc7e978dc
+  md5: 5a6bde274af5252392b446ead19047d0
+  depends:
+  - __glibc >=2.17,<3.0.a0
+  - libgcc >=13
+  - libstdcxx >=13
+  - libgcc >=13
+  license: GPL-3.0-or-later
+  license_family: GPL
+  size: 136130
+  timestamp: 1745559387060
+- conda: https://prefix.dev/conda-forge/linux-64/rattler-build-0.47.0-h60886be_0.conda
+  sha256: aa71bcaf81c71da4a9137777249970c426a37afd46b7960b3e8c397f553a7f40
+  md5: 98366f1ada223a785f0dc24ed211a99c
+  depends:
+  - patchelf
+  - libgcc >=14
+  - __glibc >=2.17,<3.0.a0
+  - openssl >=3.5.2,<4.0a0
+  constrains:
+  - __glibc >=2.17
+  license: BSD-3-Clause
+  license_family: BSD
+  size: 16827195
+  timestamp: 1756921257075
+- conda: https://prefix.dev/conda-forge/osx-64/rattler-build-0.47.0-h9113d71_0.conda
+  sha256: 03d8c45aec0e1d8e4485a54e7e61e464ecc4752c1ec6e8fdd5458c226988eba8
+  md5: b2f5ad0a287f0712c23abb0f45fbce6d
+  depends:
+  - __osx >=10.13
+  constrains:
+  - __osx >=10.13
+  license: BSD-3-Clause
+  size: 15200171
+  timestamp: 1756921285627
+- conda: https://prefix.dev/conda-forge/osx-arm64/rattler-build-0.47.0-h8d80559_0.conda
+  sha256: d747d7d36bd38d37f6e80cb78358c373fb5776147e21f9da4121e736f9212796
+  md5: dd3bf0dde45e18b8644b97a401f08ba2
+  depends:
+  - __osx >=11.0
+  constrains:
+  - __osx >=11.0
+  license: BSD-3-Clause
+  license_family: BSD
+  size: 14273395
+  timestamp: 1756921328894
+- conda: https://prefix.dev/conda-forge/win-64/rattler-build-0.47.0-h18a1a76_0.conda
+  sha256: 30e17e3741a7d98b937198cf2f4e6eedbadac9ecb0725334c63e2960cd5a5bc3
+  md5: c8e0123a1fdee1980eff4ea01fbaac88
+  depends:
+  - vc >=14.3,<15
+  - vc14_runtime >=14.44.35208
+  - ucrt >=10.0.20348.0
+  - vc >=14.3,<15
+  - vc14_runtime >=14.44.35208
+  - ucrt >=10.0.20348.0
+  license: BSD-3-Clause
+  license_family: BSD
+  size: 17784676
+  timestamp: 1756921275818
+- conda: https://prefix.dev/conda-forge/win-64/ucrt-10.0.26100.0-h57928b3_0.conda
+  sha256: 3005729dce6f3d3f5ec91dfc49fc75a0095f9cd23bab49efb899657297ac91a5
+  md5: 71b24316859acd00bdb8b38f5e2ce328
+  constrains:
+  - vc14_runtime >=14.29.30037
+  - vs2015_runtime >=14.29.30037
+  license: LicenseRef-MicrosoftWindowsSDK10
+  size: 694692
+  timestamp: 1756385147981
+- conda: https://prefix.dev/conda-forge/win-64/vc-14.3-h41ae7f8_31.conda
+  sha256: cb357591d069a1e6cb74199a8a43a7e3611f72a6caed9faa49dbb3d7a0a98e0b
+  md5: 28f4ca1e0337d0f27afb8602663c5723
+  depends:
+  - vc14_runtime >=14.44.35208
+  track_features:
+  - vc14
+  license: BSD-3-Clause
+  license_family: BSD
+  size: 18249
+  timestamp: 1753739241465
+- conda: https://prefix.dev/conda-forge/win-64/vc14_runtime-14.44.35208-h818238b_31.conda
+  sha256: af4b4b354b87a9a8d05b8064ff1ea0b47083274f7c30b4eb96bc2312c9b5f08f
+  md5: 603e41da40a765fd47995faa021da946
+  depends:
+  - ucrt >=10.0.20348.0
+  - vcomp14 14.44.35208 h818238b_31
+  constrains:
+  - vs2015_runtime 14.44.35208.* *_31
+  license: LicenseRef-MicrosoftVisualCpp2015-2022Runtime
+  license_family: Proprietary
+  size: 682424
+  timestamp: 1753739239305
+- conda: https://prefix.dev/conda-forge/win-64/vcomp14-14.44.35208-h818238b_31.conda
+  sha256: 67b317b64f47635415776718d25170a9a6f9a1218c0f5a6202bfd687e07b6ea4
+  md5: a6b1d5c1fc3cb89f88f7179ee6a9afe3
+  depends:
+  - ucrt >=10.0.20348.0
+  constrains:
+  - vs2015_runtime 14.44.35208.* *_31
+  license: LicenseRef-MicrosoftVisualCpp2015-2022Runtime
+  license_family: Proprietary
+  size: 113963
+  timestamp: 1753739198723
diff --git a/static/pixi.toml b/static/pixi.toml
new file mode 100644
index 0000000..7a8392e
--- /dev/null
+++ b/static/pixi.toml
@@ -0,0 +1,22 @@
+[workspace]
+channels = ["https://prefix.dev/conda-forge"]
+platforms = ["osx-arm64", "osx-64", "linux-64", "win-64"]
+preview = ["pixi-build"]
+
+[dependencies]
+mess-static = { path = "." }
+
+[package]
+name = "mess-static"
+
+[package.build]
+backend = { name = "pixi-build-rattler-build", version = "0.3.*" }
+
+[feature.dev.dependencies]
+rattler-build = "*"
+
+[feature.dev.tasks]
+upload = "rattler-build upload anaconda -o Auto-Mech *.conda || true"
+
+[environments]
+dev = ["dev"]
diff --git a/static/recipe.yaml b/static/recipe.yaml
index 0f70ab8..1676fe2 100644
--- a/static/recipe.yaml
+++ b/static/recipe.yaml
@@ -1,6 +1,6 @@
 package:
   name: mess-static
-  version: "2024.5.16"
+  version: "2025.9.0"
 
 source:
   path: .