Typerighter

Free plan APISelf-hosted

What Typerighter is

Typerighter is an open-source document-checking system that applies rules defined by its users, in a role similar to a spelling or grammar checker. It has two services: the Rule Manager maintains the rule corpus and publishes it for use, while the Checker reviews submitted documents and returns matching text. A match identifies the relevant text range, explains the match, and can include suggestions. Rules may be user-defined regular expressions, user-defined LanguageTool XML patterns, or predefined LanguageTool core rules. The Guardian uses Typerighter to check content against its style guide.

For ProseMirror editors, the companion prosemirror-typerighter plugin supports document validation and lets users review suggestions and apply changes. The Checker can also operate as a standalone REST service, although requests require a valid pan-domain authentication cookie. The Rule Manager stores rules in PostgreSQL and publishes a JSON artifact to S3 for the Checker. Both services are written in Scala using the Play framework. Deployment assumes AWS, defaults to the eu-west-1 region, and uses the Guardian’s riff-raff platform. Typerighter is licensed under Apache-2.0 and requires deployment and configuration; the project notes Guardian-specific assumptions and invites work to make it easier to use in other institutional settings.

Who it suits

Typerighter suits rule owners who maintain a style or document rule set and rule users who check copy against it. It is especially relevant to teams using ProseMirror or building an authenticated REST integration, provided they can handle deployment and configuration.

What it does well

Supports custom regular-expression and LanguageTool rules.
Explains matches and identifies the affected text range.
Lets users review suggestions and apply changes through ProseMirror.
Can operate as a standalone REST service.
Apache-2.0 licensed open-source software.

What to know first

Requires deployment and configuration.
Deployment assumes AWS and the Guardian’s riff-raff platform.
REST requests require a valid pan-domain authentication cookie.
The repository includes Guardian-specific assumptions.

Limits

The free Apache-2.0 software requires deployment and configuration. Its deployment assumptions include AWS and the Guardian’s riff-raff platform, and REST requests require a valid pan-domain authentication cookie.

Plans

Plan	Billed and limits	Price
Open source	Apache-2.0 licensed software · requires deployment and configuration	Free

As github.com lists them, read 9 Oct 2026. The maker's own page has the final word.

Getting started

Visit the Typerighter GitHub repository.
Deploy and configure the Rule Manager and Checker services.
Set up the assumed AWS deployment, using the default eu-west-1 region if appropriate.
Maintain and publish rules through the Rule Manager.
Integrate with ProseMirror using the companion plugin, or make authenticated REST requests to the Checker.

Verdict

Choose Typerighter if you need user-maintained rules for checking copy and can deploy and configure its services. Look elsewhere if your team needs a ready-to-use service without Guardian-specific deployment assumptions.

Questions

Is Typerighter free?

Yes. It is open-source software licensed under Apache-2.0, priced at $0. Deployment and configuration are required.

What platforms does Typerighter support?

It is available as an API and for self-hosting. It can integrate with the ProseMirror editor through a companion plugin.

Can teams define their own style rules?

Yes. Rules can include user-defined regular expressions and LanguageTool XML patterns, as well as predefined LanguageTool core rules.

Does Typerighter suggest edits?

Matches include an explanation and relevant suggestions. The ProseMirror plugin lets users review suggestions and apply changes.

What is required for REST access?

The Checker can function as a standalone REST service, and requests require a valid pan-domain authentication cookie.

What are Typerighter’s deployment assumptions?

The project assumes AWS cloud services, defaults to eu-west-1, and uses the Guardian’s riff-raff deployment platform.

Facts from Typerighter's own pages

Accuracy and control: The project vision prioritizes accurate matches, explains why text was matched, and leaves every suggested edit under the user's control. · github.com, 9 Oct 2026
Custom integration: The Checker can function as a standalone REST service, and requests require a valid pan-domain authentication cookie. · github.com, 9 Oct 2026
Deployment: The project assumes AWS cloud services, defaults to the eu-west-1 region, and uses the Guardian's riff-raff deployment platform. · github.com, 9 Oct 2026
Deployment assumptions: The repository assumes AWS cloud services, defaults to the eu-west-1 region, and uses the Guardian's riff-raff deployment platform. · github.com, 9 Oct 2026
Designed for: The project vision describes a document-proofing service intended to be available across internal tools and other applications that publish text. · github.com, 9 Oct 2026
Document checking: The Checker service accepts document check requests and returns matches from the rule corpus. · github.com, 9 Oct 2026
Editor integration: The companion prosemirror-typerighter plugin lets a ProseMirror document be validated and provides an interface to review suggestions and apply changes. · github.com, 9 Oct 2026
Guardian use: The Guardian uses Typerighter to check content against its style guide. · github.com, 9 Oct 2026
Implementation: The Checker and Rule Manager are Scala services built with the Play framework. · github.com, 9 Oct 2026
Integration: The prosemirror-typerighter plugin integrates Typerighter with the ProseMirror rich text editor and lets users review suggestions and apply changes. · github.com, 9 Oct 2026
Intended users: The documented roles are rule owners who maintain rules and rule users who check copy against them. · github.com, 9 Oct 2026
License: The repository is published under the Apache-2.0 license. · github.com, 9 Oct 2026
Match details: Matches include the applicable text range, an explanation, and relevant suggestions. · github.com, 9 Oct 2026
Notable limitation: The repository states that it contains Guardian-specific assumptions and invites contributions to make the project easier to use in other institutional contexts. · github.com, 9 Oct 2026
Origin story: The Guardian says Typerighter began as a tool to flag text issues and was later built into its Composer editing software. · theguardian.com, 9 Oct 2026
Project goal: The project vision describes a document proofing service intended to be available wherever authors write and easy to integrate into applications. · github.com, 9 Oct 2026
Purpose: Typerighter checks documents against user-defined rules and is designed to work like a spelling or grammar checker. · github.com, 9 Oct 2026
REST access: Typerighter can function as a standalone REST platform, and requests require a valid pan-domain authentication cookie. · github.com, 9 Oct 2026
Results: Matches include the applicable text range, an explanation, and any relevant suggestions. · github.com, 9 Oct 2026
Rule management: The Rule Manager maintains the rule corpus and publishes it as an artifact consumed by the Checker service. · github.com, 9 Oct 2026
Rule storage: The Rule Manager stores data in Postgres and publishes a JSON rules artifact to S3 for the Checker to consume. · github.com, 9 Oct 2026
Rule types: Its rules include user-defined regular expressions, user-defined LanguageTool XML patterns, and predefined LanguageTool core rules. · github.com, 9 Oct 2026
Technology: The Checker and Rule Manager are Scala services built with the Play framework, and the Rule Manager stores data in PostgreSQL. · github.com, 9 Oct 2026
Two services: Typerighter consists of a Rule Manager that manages and publishes rules and a Checker that checks copy against them. · github.com, 9 Oct 2026

Where Typerighter stands on Freedom251

Writing Style Checkers#17 of 29