---
title: "Can DeepSeek-R1 distilled models produce strict JSON without constrained decoding?"  
description: "Can DeepSeek-R1 distilled models produce strict JSON without constrained decoding?"  
author: "Shamma Al Marzooqi"  
published: 2026-10-23  
updated: 2026-10-23  
canonical: https://www.mindstick.com/forum/162877/can-deepseek-r1-distilled-models-produce-strict-json-without-constrained-decoding  
category: "DeepSeek Models"  
tags: ["DeepSeek", "R1 distilled models", "JSON output", "Local inference"]  
reading_time: 1 minute  

---

# Can DeepSeek-R1 distilled models produce strict JSON without constrained decoding?

I’m testing a DeepSeek-R1 distilled model for a small extraction task. The response usually contains the right information, but it sometimes adds a short explanation before the JSON or uses a field name that isn’t in my schema.

For people serving these models locally, can prompting alone make the output dependable enough for a parser, or do you need constrained decoding? I’m also wondering whether results vary noticeably between serving engines such as vLLM and Ollama.


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Original Source: https://www.mindstick.com/forum/162877/can-deepseek-r1-distilled-models-produce-strict-json-without-constrained-decoding

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