stripe-python Problem with uploading binary files with

The Fix

pip install stripe==14.4.0a2

Based on closed stripe/stripe-python issue #217 · PR/commit linked

Production note: Most teams hit this during upgrades or environment changes. Roll out with a canary and smoke critical endpoints (health, OpenAPI/docs) before 100%.

Open PR/Commit

@@ -18,8 +18,11 @@ def add_params(self, params):
             self._write(self.line_break)
             if hasattr(value, 'read'):
-                self._write("Content-Disposition: form-data; name=\"%s\"; "
-                            "filename=\"%s\"" % (key, value.name))
+                self._write("Content-Disposition: form-data; name=\"")

fix.md

Option A — Upgrade to fixed release\npip install stripe==14.4.0a2\nWhen NOT to use: Do not apply this fix if the application requires strict encoding for text files.\n\n

Why This Fix Works in Production

Trigger: Problem with uploading binary files with Python 3
Mechanism: The file upload method incorrectly handles binary files in Python 3 due to encoding assumptions
Why the fix works: Fixes the handling of ASCII/Unicode in file uploads for both Python 2 and 3, addressing the issue of binary file uploads failing. (first fixed release: 14.4.0a2).

Production impact:

If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.

Why This Breaks in Prod

Shows up under Python 3.5 in real deployments (not just unit tests).
The file upload method incorrectly handles binary files in Python 3 due to encoding assumptions
Surfaces as: Traceback (most recent call last):\n <snip>\n File "/Users/ob/.pyenv/versions/3.5.1/lib/python3.5/site-packages/stripe/multipart_data_generator.py", line 28, in add_params\n…

Proof / Evidence

GitHub issue: #217
Fix PR: https://github.com/stripe/stripe-python/pull/218
First fixed release: 14.4.0a2
Reproduced locally: No (not executed)
Last verified: 2026-02-08
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.45

Discussion

High-signal excerpts from the issue thread (symptoms, repros, edge-cases).

Jump to Sources Open on GitHub

“Actually, while we're at it, we should also handle the case where Python 2 will have to deal with Unicode strings.”

@olivierbellone · 2016-03-23 · source

“> @brandur, any thoughts? Should I proceed with the above? Yes! Looks very reasonable to me. We should also consider augmenting the test suite for…”

@brandur · 2016-03-23 · source

Failure Signature (Search String)

Problem with uploading binary files with Python 3

Error Message

Stack trace

error.txt

Error Message
-------------
Traceback (most recent call last):\n  <snip>\n  File "/Users/ob/.pyenv/versions/3.5.1/lib/python3.5/site-packages/stripe/multipart_data_generator.py", line 28, in add_params\n    self._write_file(value)\n  File "/Users/ob/.pyenv/versions/3.5.1/lib/python3.5/site-packages/stripe/multipart_data_generator.py", line 54, in _write_file\n    file_contents = f.read(self.chunk_size)\n  File "/Users/ob/.pyenv/versions/3.5.1/lib/python3.5/codecs.py", line 321, in decode\n    (result, consumed) = self._buffer_decode(data, self.errors, final)

Stack trace

error.txt

Error Message
-------------
Traceback (most recent call last):\n  <snip>\n  File "/Users/ob/.pyenv/versions/3.5.1/lib/python3.5/site-packages/stripe/multipart_data_generator.py", line 28, in add_params\n    self._write_file(value)\n  File "/Users/ob/.pyenv/versions/3.5.1/lib/python3.5/site-packages/stripe/multipart_data_generator.py", line 57, in _write_file\n    self._write(file_contents)\n  File "/Users/ob/.pyenv/versions/3.5.1/lib/python3.5/site-packages/stripe/multipart_data_generator.py", line 50, in _write\n    self.data.write(bytes(value, 'utf-8'))

Environment

Python: 3.5

What Broke

Uploading binary files fails, causing application errors and potential data loss.

Why It Broke

The file upload method incorrectly handles binary files in Python 3 due to encoding assumptions

Fix Options (Details)

Option A — Upgrade to fixed release Safe default (recommended)

pip install stripe==14.4.0a2

When NOT to use: Do not apply this fix if the application requires strict encoding for text files.

Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.

Fix reference: https://github.com/stripe/stripe-python/pull/218

First fixed release: 14.4.0a2

Last verified: 2026-02-08. Validate in your environment.

When NOT to Use This Fix

Do not apply this fix if the application requires strict encoding for text files.

Did This Fix Work in Your Case?

Quick signal helps us prioritize which fixes to verify and improve.

Prevention

Capture the exact failing error string in logs and tests so you can reproduce via a minimal script.
Pin production dependencies and upgrade only with a reproducible test that hits the failing path.

Version Compatibility Table

Version	Status
14.4.0a2	Fixed

Related Issues

No related fixes found.

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Related clusters: Data consistency Other Payments

Sources

We don’t republish the full GitHub discussion text. Use the links above for context.

stripe-python Problem with uploading binary files with Python 3 (Fix)