Best Practices for Using Structured Output from LLMs

In plain words

This resource provides guidance on implementing structured output from large language models. It is designed for developers and engineers working with LLMs who need to ensure consistent, predictable responses in standardized formats. The material focuses on practical techniques and methodologies for constraining LLM outputs to structured schemas, helping teams integrate language models more reliably into production systems.

written from the facts on this page · September 2026

From the sources

The Instill AI platform shut down on 29 May 2026. Thank you for trusting us with your work. We still care deeply about helping people turn complex information into work they can trust, and we're exploring new ways to support that work. If Instill helped you, we'd love to hear how you used it — reach us anytime at [email protected]from instill.tech

• 
  A new benchmark for testing LLMs for deterministic outputsApr 2026 · interfaze.ai · ▲60

  When building workflows that rely on LLMs, we commonly use structured output for programmatic use cases like converting an invoice into rows or meeting transcripts into tickets or even complex PDFs into database entries. The model may return the schema you want, but with hallucinated values like `invoice_date` being off by 2 months or the transcript array ordered wrongly. The JSON is valid, but the values are not. Structured output today is a big part of using LLMs, especially when building deterministic workflows. Current structured output benchmarks (e.g., JSONSchemaBench) only validate…

• 
  Marsha – An LLM-Based Programming Language2023 · github.com · ▲140

  Marsha is a functional, higher-level, English-based programming language that gets compiled into tested Python software by an LLM - alantech/marsha

• 
  Why write code if the LLM can just do the thing? (web app experiment)Nov 2025 · github.com · ▲436

  I spent a few hours last weekend testing whether AI can replace code by executing directly. Built a contact manager where every HTTP request goes to an LLM with three tools: database (SQLite), webResponse (HTML/JSON/JS), and updateMemory (feedback). No routes, no controllers, no business logic. The AI designs schemas on first request, generates UIs from paths alone, and evolves based on natural language feedback. It works—forms submit, data persists, APIs return JSON—but it's catastrophically slow (30-60s per request), absurdly expensive ($0.05/request), and has zero UI…

• 
  AI Timeline – 171 LLMs from Transformer (2017) to GPT-5.3 (2026)Feb 2026 · llm-timeline.com · ▲174

  Interactive timeline of every major Large Language Model. Filterable by open/closed source, searchable, 54 organizations tracked.

• 
  LangSmith2023 · langchain.com · ▲350

  Build and deploy LLM applications with confidence

• 
  Structured output from LLMs without reprompting2023 · automorphic.ai · ▲174

  Built a tool for transforming unstructured data into structured outputs using language models (with 100% adherence). If you're facing problems getting GPT to adhere to a schema (JSON, XML, etc.) or regex, need to bulk process some unstructured data, or generate synthetic data, check it out. We run our own tuned model (you can self-host if you want), so, we're able to have incredibly fine grained control over text generation. Repository: https://github.com/automorphic-ai/trex Playground: https://automorphic.ai/playground

• 
  SimCity, but with Permits▲895

  A free city-building game in your browser. You are the mayor. You know what the city needs. Now get it past the zoning board, the neighbors, the appeals court and the next election.

  Life & fun · 1d ago · permit.petercai.com

• IV
  I've been paying for a rural Tanzanian's education for 10 years▲778

  Life & fun · 13d ago · tanzaniaeducationproject.org

• 
  Bigwords.page – Turn any screen into a sign. The URL is the app▲728

  Turn a phone, tablet or TV into a sign. Type a message and it fills the screen: welcome signs, timers, Wi-Fi passwords and more. No app, no account, free.

  Life & fun · 14d ago · bigwords.page

• 
  Guitoro, a virtual guitar you strum with your keyboard▲573

  Play a free virtual guitar online with your keyboard or by touch. Slow songs down and see every chord, string and strum. Acoustic, classic, electric and bass.

  Life & fun · 8d ago · guitoro.com

• 
  See *almost* any carriers phone settings▲432

  Carrier settings from iPhone, Pixel and Galaxy firmware, decoded and compared: APNs, VoLTE, 5G and Wi-Fi Calling per carrier, and what each build changed.

  Life & fun · 12d ago · carrierexplode.com

• 
  The whole Solar System and every tracked satellite, live in the browser▲407

  Life & fun · 22d ago · space.bl2.net

• 
  Wispr Flow▲2,732

  Speak naturally, write perfectly & 3x faster in every app

  AI · 2024 · wisprflow.ai

• 
  Pathway▲1,335

  Get user insights 10x faster

  Work · 2024 · wynde.io

• 
  BeforeSunset AI 2.0▲1,267

  Personalized AI daily planning that suits your life

  AI · 2024 · beforesunset.ai

• 
  Osmos▲1,194

  Match with like-minded professionals for 1:1 conversations

  Growth · 2024

• 
  Carrot Care▲1,168

  Understand & optimise your bloodwork

  Life & fun · 2024 · carrotcare.health

• 
  Polar▲1,167

  An open source monetization platform for developers

  Dev tools · 2024 · polar.sh