# Best LLM for JSON & Schema Output

> Updated Oct 20, 2026 · evidence through Oct 20, 2026. Synthesized from cited community evidence and open benchmarks, not vendor marketing. Canonical page: https://modelmatchbook.com/best/extraction-schema

DeepSeek V4.1 Flash ranks first for JSON & Schema Output as of October 20, 2026. It scores 79.25% on LiveBench Data Analysis (#14 of 59), including table joining and reformatting tasks. GPT-6.1 Sol is the next-ranked alternative. It scores 82.66% on LiveBench Data Analysis (#2 of 59), including table joining and reformatting tasks. [1,2]

## 1. DeepSeek V4.1 Flash
https://modelmatchbook.com/models/deepseek/deepseek-v4.1-flash-20260910

DeepSeek V4.1 Flash scores 79.25% on LiveBench Data Analysis (#14 of 59), including table joining and reformatting tasks.

**Best when:** Its strongest result for this task is on LiveBench Data Analysis, which measures working with tables and structured data. [1]

## 2. GPT-6.1 Sol
https://modelmatchbook.com/models/openai/gpt-6.1-sol-20260929

GPT-6.1 Sol scores 82.66% on LiveBench Data Analysis (#2 of 59), including table joining and reformatting tasks.

**Best when:** Its strongest result for this task is on LiveBench Data Analysis, which measures working with tables and structured data. [2]

## 3. Kimi K3
https://modelmatchbook.com/models/moonshotai/kimi-k3-20260715

Kimi K3 ranks #14 of 152 on LMArena's overall text arena (Elo 1487), based on blind human preference votes.

**Best when:** Its strongest result for this task is on LMArena Text, which measures general reasoning and instruction following. [3]

## 4. GLM 5.3 Flash
https://modelmatchbook.com/models/z-ai/glm-5.3-flash-20260826

GLM 5.3 Flash scores 76.4% on LiveBench Data Analysis (#27 of 59), including table joining and reformatting tasks.

**Best when:** Its strongest result for this task is on LiveBench Data Analysis, which measures working with tables and structured data. [4]

## 5. Qwen3.8 27B
https://modelmatchbook.com/models/qwen/qwen3.8-27b-20260814

Qwen3.8 27B scores 76.59% on LiveBench Data Analysis (#24 of 59), including table joining and reformatting tasks.

**Best when:** Its strongest result for this task is on LiveBench Data Analysis, which measures working with tables and structured data. [5]

## 6. Muse Spark 1.3
https://modelmatchbook.com/models/meta/muse-spark-1.3-20260902

Muse Spark 1.3 scores 79.57% on LiveBench Data Analysis (#9 of 59), including table joining and reformatting tasks.

**Best when:** Its strongest result for this task is on LiveBench Data Analysis, which measures working with tables and structured data. [6]

## 7. GPT-6 Astra
https://modelmatchbook.com/models/openai/gpt-6-astra-20260903

GPT-6 Astra scores 82.97% on LiveBench Data Analysis (#1 of 59), including table joining and reformatting tasks.

**Best when:** Its strongest result for this task is on LiveBench Data Analysis, which measures working with tables and structured data. [7]

## 8. Claude Opus 5.5
https://modelmatchbook.com/models/anthropic/claude-opus-5.5-20260921

Claude Opus 5.5 ranks #3 of 152 on LMArena's overall text arena (Elo 1508), based on blind human preference votes.

**Best when:** Its strongest result for this task is on LMArena Text, which measures general reasoning and instruction following. [8]

## FAQ

**What is the best model for JSON & Schema Output?**

DeepSeek V4.1 Flash ranks first as of October 20, 2026. DeepSeek V4.1 Flash scores 79.25% on LiveBench Data Analysis (#14 of 59), including table joining and reformatting tasks. [1]

**What is the best alternative to DeepSeek V4.1 Flash?**

GPT-6.1 Sol ranks second. GPT-6.1 Sol scores 82.66% on LiveBench Data Analysis (#2 of 59), including table joining and reformatting tasks. [2]

**Can I self-host the top pick for JSON & Schema Output?**

Yes. DeepSeek V4.1 Flash is open-weight, so it can run on your own hardware as well as through hosted routes. [1]

## Sources
1. "Within the 59 catalog models matched to this evaluation: Scores 79.25% on LiveBench Data Analysis (#14 of 59), including table joining and reformatting tasks." (LiveBench Data Analysis, https://livebench.ai/)
2. "Within the 59 catalog models matched to this evaluation: Scores 82.66% on LiveBench Data Analysis (#2 of 59), including table joining and reformatting tasks." (LiveBench Data Analysis, https://livebench.ai/)
3. "Within the 152 catalog models matched to this evaluation: Ranks #14 of 152 on LMArena's overall text arena (Elo 1487), based on blind human preference votes." (LMArena text arena, https://lmarena.ai/leaderboard)
4. "Within the 59 catalog models matched to this evaluation: Scores 76.4% on LiveBench Data Analysis (#27 of 59), including table joining and reformatting tasks." (LiveBench Data Analysis, https://livebench.ai/)
5. "Within the 59 catalog models matched to this evaluation: Scores 76.59% on LiveBench Data Analysis (#24 of 59), including table joining and reformatting tasks." (LiveBench Data Analysis, https://livebench.ai/)
6. "Within the 59 catalog models matched to this evaluation: Scores 79.57% on LiveBench Data Analysis (#9 of 59), including table joining and reformatting tasks." (LiveBench Data Analysis, https://livebench.ai/)
7. "Within the 59 catalog models matched to this evaluation: Scores 82.97% on LiveBench Data Analysis (#1 of 59), including table joining and reformatting tasks." (LiveBench Data Analysis, https://livebench.ai/)
8. "Within the 152 catalog models matched to this evaluation: Ranks #3 of 152 on LMArena's overall text arena (Elo 1508), based on blind human preference votes." (LMArena text arena, https://lmarena.ai/leaderboard)