diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 646eee7b..819d8691 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.497.0"
+  ".": "0.498.0"
 }
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f6f69af5..c44d0448 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## 0.498.0 (2026-04-27)
+
+Full Changelog: [v0.497.0...v0.498.0](https://github.com/Increase/increase-python/compare/v0.497.0...v0.498.0)
+
+### Features
+
+* support setting headers via env ([ae4500c](https://github.com/Increase/increase-python/commit/ae4500cfb7c6d4e734542e9371001cfe9b4750b3))
+
 ## 0.497.0 (2026-04-27)
 
 Full Changelog: [v0.496.0...v0.497.0](https://github.com/Increase/increase-python/compare/v0.496.0...v0.497.0)
diff --git a/pyproject.toml b/pyproject.toml
index 4df8601c..648f5af8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "increase"
-version = "0.497.0"
+version = "0.498.0"
 description = "The official Python library for the increase API"
 dynamic = ["readme"]
 license = "Apache-2.0"
diff --git a/src/increase/_client.py b/src/increase/_client.py
index 899a105a..e0723d90 100644
--- a/src/increase/_client.py
+++ b/src/increase/_client.py
@@ -22,6 +22,7 @@
 from ._utils import (
     is_given,
     is_mapping,
+    is_mapping_t,
     get_async_library,
 )
 from ._compat import cached_property
@@ -264,6 +265,15 @@ def __init__(
             except KeyError as exc:
                 raise ValueError(f"Unknown environment: {environment}") from exc
 
+        custom_headers_env = os.environ.get("INCREASE_CUSTOM_HEADERS")
+        if custom_headers_env is not None:
+            parsed: dict[str, str] = {}
+            for line in custom_headers_env.split("\n"):
+                colon = line.find(":")
+                if colon >= 0:
+                    parsed[line[:colon].strip()] = line[colon + 1 :].strip()
+            default_headers = {**parsed, **(default_headers if is_mapping_t(default_headers) else {})}
+
         super().__init__(
             version=__version__,
             base_url=base_url,
@@ -857,6 +867,15 @@ def __init__(
             except KeyError as exc:
                 raise ValueError(f"Unknown environment: {environment}") from exc
 
+        custom_headers_env = os.environ.get("INCREASE_CUSTOM_HEADERS")
+        if custom_headers_env is not None:
+            parsed: dict[str, str] = {}
+            for line in custom_headers_env.split("\n"):
+                colon = line.find(":")
+                if colon >= 0:
+                    parsed[line[:colon].strip()] = line[colon + 1 :].strip()
+            default_headers = {**parsed, **(default_headers if is_mapping_t(default_headers) else {})}
+
         super().__init__(
             version=__version__,
             base_url=base_url,
diff --git a/src/increase/_version.py b/src/increase/_version.py
index 86e445cb..315f304f 100644
--- a/src/increase/_version.py
+++ b/src/increase/_version.py
@@ -1,4 +1,4 @@
 # File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
 __title__ = "increase"
-__version__ = "0.497.0"  # x-release-please-version
+__version__ = "0.498.0"  # x-release-please-version