Welcome

API Overview SDK Overview

Welcome to the documentation for Sapling.ai's developer platform. 🚀 Sapling is a platform for building language model applications. Sapling's API provides endpoints for text preprocessing, classification, prediction, correction, and more. Sapling's SDK provides convenient wrappers around the API, as well as UI components for quickly integrating LM-powered functionality in your web application.

Announcements

November 13, 2026: A more accurate multilingual AI detector model for the 15 supported non-English languages. It flags less human-written text as AI and catches more AI-written text. No request changes are needed, and you can pin a previous version.
November 12, 2026: The free Source Match API compares a text against up to 20 documents you supply and returns shared verbatim passages and their positions. It checks only the sources in your request, not the open web.
November 4, 2026: The default English AI detector model flags far less human-written text such as customer reviews and testimonials as AI. It catches slightly less AI-written text overall. No request changes are needed, and you can pin a previous version to keep the old scores.
November 4, 2026: The AI detector API now also scores Polish, Chinese, Arabic, Russian, Swedish, Korean, Turkish and Romanian with the multilingual model, instead of the English model, and the other non-English languages have moved to the updated model. No request changes are needed, and lang accepts the new language codes too. Scores change for requests that don't pin a version, so recheck any thresholds you set for these languages.
November 3, 2026: More accurate AI detector models in every supported language. They flag far less human-written text with bullets or headings as AI, and the English model catches more text from recent models such as Claude 5.5. No request changes are needed, and you can pin a previous version to keep the old scores.
November 2, 2026: The free Job Description Match API measures how closely a resume overlaps with the job description it was submitted for, with keyword coverage and passages shared word for word.
October 2026: AI detector responses now include a verdict and flagged segments, create_report returns a shareable report link, and zero_retention keeps no copy of the text.

Getting Started

Get started by following the instructions here. You can see some of these capabilities by visiting our Demo page.

From there, you can start using the Sapling HTTP API or SDK. To use Sapling's language tools directly from an AI assistant, install the Sapling MCP Server.

You can also try out Sapling using Postman or Zapier. For questions, email us or join our Discord:

Send HTTP requests	Create Zaps	Chat with us

Code Examples

Find example code in our GitHub repository, including examples for Python and JavaScript (React, Angular). Start a GitHub issue if your use case isn't handled.

Use Cases

Here are some of the things you can do with Sapling:

⚙️ Integrate deep learning-powered grammar/spell checking into any application, either through the SDK or through the grammar check API.
✨ Autocomplete phrases and sentences to save users time typing.
😀 Check the tone of messages.
Check the sentiment of messages.
🟰 Search for semantically similar terms to augment tagging and search.
🔍 Pull semantically relevant responses for knowledge-base retrieval and search.
💫 Rephrase sentences to adjust formality, length, or syntax.
🕵🏽‍♀️ Detect AI-generated content with the AI detector API or score the quality of content (contact us for details on quality scoring).

You can try out many of the examples on our utilities page.

New functionality is being released every week. Contact us to learn more or to discuss if Sapling can support your use case.

Key Principles

Sapling allows you to easily integrate language model-powered functionality into your application.

End-to-end: Sapling is designed to handle the entire stack, from preprocessing text inputs, to model inference, to postprocessing outputs, to scoring and filtering outputs. It covers the last mile that's required for production systems.
Predictable: Sapling is designed to not hallucinate or produce unexpected texts. It returns structured outputs that can reliably be used by production systems.
Efficient: Sapling is designed for use in real-time settings. This is true for both Sapling's cloud API as well as its self-hosted offerings.
Turnkey: For many applications, Sapling can be integrated with just a few lines of JavaScript/Python code. We ensure that the API/SDK are stable and well-documented (see our SLA).
Secure: Whether you use our cloud and require finetuning or you require an airgapped deployment with zero data retention, Sapling can support your data security requirements.

Subscribing

Signing up and generating an API key will start you on a free trial of the API. There is a character limit and a 1-month expiration date for the trial.

Subscribe to remove quota limits and begin usage-based pricing (billed monthly). This will also increase the character limit (up to 10 million characters per day for the /edits endpoint, as one example) and upgrade the key so that it does not expire.