diff --git a/README.md b/README.md
index 15939642..ae358912 100644
--- a/README.md
+++ b/README.md
@@ -114,6 +114,30 @@ Numerical integration:
     >>> acb.integral(lambda x, _: (-x**2).exp(), -100, 100) ** 2
     [3.141592653589793238462643383 +/- 3.11e-28]
 
+Cython API
+-------------------------------------
+
+The PyPI/conda wheels install the ``.pxd`` files. A third-party Cython
+module can then ``cimport`` the ``acb`` class and the libflint declarations
+and operate on the underlying ``acb_t``:
+
+.. code-block:: cython
+
+    from flint.types.acb cimport acb
+    from flint.flintlib.functions.acb cimport acb_exp, acb_t
+    from flint.flint_base.flint_context cimport getprec
+
+    def exp_c(acb z):
+        cdef acb out = acb.__new__(acb)
+        acb_exp(out.val, z.val, getprec())
+        return out
+
+Compiling that still needs the FLINT C headers (``flint/acb.h``) and
+``libflint`` on the linker line, same versions as the ``python-flint``
+build. The Windows PyPI wheel ships ``libflint`` but not the headers;
+use a FLINT development install (for example conda-forge ``libflint``)
+when building the extension.
+
 To do
 -------------------------------------
 
diff --git a/src/flint/flint_base/meson.build b/src/flint/flint_base/meson.build
index 328494f2..8a84a5e3 100644
--- a/src/flint/flint_base/meson.build
+++ b/src/flint/flint_base/meson.build
@@ -4,6 +4,8 @@ pyfiles = [
   '__init__.py',
   'flint_base.pyi',
   'flint_context.pyi',
+  'flint_base.pxd',
+  'flint_context.pxd',
 ]
 
 exts = [
diff --git a/src/flint/flintlib/functions/meson.build b/src/flint/flintlib/functions/meson.build
new file mode 100644
index 00000000..5593bfd0
--- /dev/null
+++ b/src/flint/flintlib/functions/meson.build
@@ -0,0 +1,88 @@
+py.install_sources(
+  [
+    '__init__.py',
+    '__init__.pxd',
+    'acb.pxd',
+    'acb_calc.pxd',
+    'acb_dft.pxd',
+    'acb_dirichlet.pxd',
+    'acb_elliptic.pxd',
+    'acb_hypgeom.pxd',
+    'acb_mat.pxd',
+    'acb_modular.pxd',
+    'acb_poly.pxd',
+    'acb_theta.pxd',
+    'arb.pxd',
+    'arb_fmpz_poly.pxd',
+    'arb_hypgeom.pxd',
+    'arb_mat.pxd',
+    'arb_poly.pxd',
+    'arf.pxd',
+    'arith.pxd',
+    'bernoulli.pxd',
+    'compat.pxd',
+    'dirichlet.pxd',
+    'flint.pxd',
+    'fmpq.pxd',
+    'fmpq_mat.pxd',
+    'fmpq_mpoly.pxd',
+    'fmpq_mpoly_factor.pxd',
+    'fmpq_poly.pxd',
+    'fmpq_vec.pxd',
+    'fmpz.pxd',
+    'fmpz_factor.pxd',
+    'fmpz_lll.pxd',
+    'fmpz_mat.pxd',
+    'fmpz_mod.pxd',
+    'fmpz_mod_mat.pxd',
+    'fmpz_mod_mpoly.pxd',
+    'fmpz_mod_mpoly_factor.pxd',
+    'fmpz_mod_poly.pxd',
+    'fmpz_mod_poly_factor.pxd',
+    'fmpz_mod_vec.pxd',
+    'fmpz_mpoly.pxd',
+    'fmpz_mpoly_factor.pxd',
+    'fmpz_mpoly_q.pxd',
+    'fmpz_poly.pxd',
+    'fmpz_poly_factor.pxd',
+    'fmpz_vec.pxd',
+    'fq.pxd',
+    'fq_default.pxd',
+    'fq_default_mat.pxd',
+    'fq_default_poly.pxd',
+    'fq_default_poly_factor.pxd',
+    'fq_mat.pxd',
+    'fq_nmod.pxd',
+    'fq_nmod_mat.pxd',
+    'fq_nmod_poly.pxd',
+    'fq_nmod_poly_factor.pxd',
+    'fq_poly.pxd',
+    'fq_poly_factor.pxd',
+    'fq_zech.pxd',
+    'fq_zech_mat.pxd',
+    'fq_zech_poly.pxd',
+    'fq_zech_poly_factor.pxd',
+    'gr.pxd',
+    'gr_domains.pxd',
+    'gr_generic.pxd',
+    'gr_implementing.pxd',
+    'gr_mat.pxd',
+    'gr_mpoly.pxd',
+    'gr_poly.pxd',
+    'gr_special.pxd',
+    'gr_vec.pxd',
+    'mag.pxd',
+    'mpoly.pxd',
+    'nmod.pxd',
+    'nmod_mat.pxd',
+    'nmod_mpoly.pxd',
+    'nmod_mpoly_factor.pxd',
+    'nmod_poly.pxd',
+    'nmod_poly_factor.pxd',
+    'nmod_vec.pxd',
+    'partitions.pxd',
+    'ulong_extras.pxd',
+  ],
+  pure: false,
+  subdir: 'flint/flintlib/functions',
+)
diff --git a/src/flint/flintlib/meson.build b/src/flint/flintlib/meson.build
new file mode 100644
index 00000000..52c1d12a
--- /dev/null
+++ b/src/flint/flintlib/meson.build
@@ -0,0 +1,13 @@
+# Cython declarations for libflint. Needed on the install path so a
+# third-party .pyx can `cimport flint.types.acb` and call acb_* on `.val`.
+py.install_sources(
+  [
+    '__init__.py',
+    'README.md',
+  ],
+  pure: false,
+  subdir: 'flint/flintlib',
+)
+
+subdir('functions')
+subdir('types')
diff --git a/src/flint/flintlib/types/meson.build b/src/flint/flintlib/types/meson.build
new file mode 100644
index 00000000..64e43753
--- /dev/null
+++ b/src/flint/flintlib/types/meson.build
@@ -0,0 +1,29 @@
+py.install_sources(
+  [
+    '__init__.py',
+    'acb.pxd',
+    'acb_calc.pxd',
+    'acb_dirichlet.pxd',
+    'acb_theta.pxd',
+    'arb.pxd',
+    'arf.pxd',
+    'arith.pxd',
+    'dirichlet.pxd',
+    'flint.pxd',
+    'fmpq.pxd',
+    'fmpz.pxd',
+    'fmpz_mod.pxd',
+    'fmpz_mod_mat_compat.pxd',
+    'fmpz_mod_poly.pxd',
+    'fq.pxd',
+    'fq_default.pxd',
+    'fq_nmod.pxd',
+    'fq_zech.pxd',
+    'gr.pxd',
+    'mpoly.pxd',
+    'nmod.pxd',
+    'undocumented.pxd',
+  ],
+  pure: false,
+  subdir: 'flint/flintlib/types',
+)
diff --git a/src/flint/meson.build b/src/flint/meson.build
index 4feb64ea..abb4e568 100644
--- a/src/flint/meson.build
+++ b/src/flint/meson.build
@@ -5,6 +5,7 @@ pyfiles = [
   'typing.py',
   'py.typed',
   'pyflint.pyi',
+  'pyflint.pxd',
 ]
 
 exts = [
@@ -17,6 +18,7 @@ pkgs = [
   'functions',
   'utils',
   'test',
+  'flintlib',
 ]
 
 py.install_sources(
diff --git a/src/flint/test/meson.build b/src/flint/test/meson.build
index 77c102c9..7c797d31 100644
--- a/src/flint/test/meson.build
+++ b/src/flint/test/meson.build
@@ -18,6 +18,7 @@ pyfiles = [
   'test_fmpz_vec.py',
   'test_docstrings.py',
   'test_dirichlet.py',
+  'test_pxd.py',
 ]
 
 py.install_sources(
diff --git a/src/flint/test/test_pxd.py b/src/flint/test/test_pxd.py
new file mode 100644
index 00000000..2f4d9087
--- /dev/null
+++ b/src/flint/test/test_pxd.py
@@ -0,0 +1,18 @@
+"""Installed wheels must ship .pxd so third-party Cython can cimport acb_t."""
+from pathlib import Path
+
+import flint
+
+
+def test_cython_pxd_files_are_installed() -> None:
+    root = Path(flint.__file__).resolve().parent
+    needed = [
+        root / "pyflint.pxd",
+        root / "types" / "acb.pxd",
+        root / "flint_base" / "flint_base.pxd",
+        root / "flintlib" / "functions" / "acb.pxd",
+        root / "flintlib" / "types" / "acb.pxd",
+        root / "flintlib" / "functions" / "acb_hypgeom.pxd",
+    ]
+    missing = [str(p.relative_to(root)) for p in needed if not p.is_file()]
+    assert missing == [], missing
diff --git a/src/flint/types/meson.build b/src/flint/types/meson.build
index 1e527091..f2dedd53 100644
--- a/src/flint/types/meson.build
+++ b/src/flint/types/meson.build
@@ -47,6 +47,42 @@ pyfiles = [
   'dirichlet.pyi',
   #
   # '_gr.pyi',
+
+  # Cython declarations for third-party cimport (acb.val is acb_t).
+  '_gr.pxd',
+  'acb.pxd',
+  'acb_mat.pxd',
+  'acb_poly.pxd',
+  'acb_series.pxd',
+  'arb.pxd',
+  'arb_mat.pxd',
+  'arb_poly.pxd',
+  'arb_series.pxd',
+  'arf.pxd',
+  'dirichlet.pxd',
+  'fmpq.pxd',
+  'fmpq_mat.pxd',
+  'fmpq_mpoly.pxd',
+  'fmpq_poly.pxd',
+  'fmpq_series.pxd',
+  'fmpq_vec.pxd',
+  'fmpz.pxd',
+  'fmpz_mat.pxd',
+  'fmpz_mod.pxd',
+  'fmpz_mod_mat.pxd',
+  'fmpz_mod_mpoly.pxd',
+  'fmpz_mod_poly.pxd',
+  'fmpz_mpoly.pxd',
+  'fmpz_poly.pxd',
+  'fmpz_series.pxd',
+  'fmpz_vec.pxd',
+  'fq_default.pxd',
+  'fq_default_poly.pxd',
+  'nmod.pxd',
+  'nmod_mat.pxd',
+  'nmod_mpoly.pxd',
+  'nmod_poly.pxd',
+  'nmod_series.pxd',
 ]
 
 exts = [
diff --git a/src/flint/utils/meson.build b/src/flint/utils/meson.build
index 8ec2da5c..4e908815 100644
--- a/src/flint/utils/meson.build
+++ b/src/flint/utils/meson.build
@@ -3,6 +3,8 @@ thisdir = 'flint/utils'
 pyfiles = [
   '__init__.py',
   'flint_exceptions.py',
+  'conversion.pxd',
+  'typecheck.pxd',
 ]
 
 exts = []