Azure Functions Python Library

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Overview

Python support for Azure Functions is based on Python 3.11, 3.12, 3.13, 3.14, and 3.15 serverless hosting on Linux, and the Functions 2.x (EOL), 3.x (EOL) and 4.0 runtime.

Here is the current status of Python in Azure Functions:

What are the supported Python versions?

What's available?

• Build, test, debug and publish using Azure Functions Core Tools (CLI) or Visual Studio Code
• Triggers / Bindings : Blob, Cosmos DB, Event Grid, Event Hub, HTTP, Kafka, MySQL, Queue, ServiceBus, SQL, Timer, and Warmup
• Create a Python Function on Linux using a custom docker image
• Triggers / Bindings : Custom binding support

Get Started

• Create your first Python function
• Developer guide
• Binding API reference
• Develop using VS Code
• Create a Python Function on Linux using a custom docker image

Give Feedback

Issues and feature requests are tracked in a variety of places. To report this feedback, please file an issue to the relevant repository below:

Durable Functions JSON serialization

azure.functions._durable_functions.df_dumps(value, *, ensure_ascii=True) preserves legacy ASCII-escaped JSON by default. Pass ensure_ascii=False to opt in to emitting ordinary Unicode literally in either loose or strict typing mode. Surrogate code units, including lone surrogates and explicit surrogate-pair strings, remain JSON-escaped so the output is safe to encode as UTF-8 and pass through protobuf string fields. ASCII DEL also retains its legacy \u007f escape. Unicode is not normalized. ASCII output, whitespace, custom-object envelopes, and strict/loose type rules are unchanged; df_loads reads both escaped and literal-Unicode payloads.

For the synthetic Python value {"text": "\u0416" * 100000} (100,000 Cyrillic characters), df_dumps(value, ensure_ascii=False) produces 200,012 UTF-8 bytes, compared with 600,012 bytes using the default or explicit ensure_ascii=True. This isolates escaping overhead; it does not measure a complete production request or remove aggregate transport limits.

Opt-in compatibility: Serialized bytes change for ordinary non-ASCII text only when selecting ensure_ascii=False, even though escaped and literal JSON decode to the same values. Applications deriving hashes, signatures, IDs, or replay decisions from serialized JSON must review their byte-dependent logic before opting in or switching back. Existing callers, including the activity trigger converter, continue to use ASCII-escaped output. Literal-Unicode output has not been validated against live hosted backends; provider integration/replay coverage and real-host staging validation are tracked in microsoft/durabletask-python#291, linked from #371.

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.