Rasa Paraphraser
github.com
What it is
Rasa Paraphraser is a free, MIT-licensed open-source tool for generating sentence alternatives that keep intended meaning while changing wording and structure. Rasa built it mainly for data augmentation in Rasa Open Source, with other paraphrasing uses also possible. The multilingual model supports 30 languages, although the README says testing has covered English, German, French, Spanish and Russian. It uses a Prism-framework neural machine translation model with decoding changes intended to increase diversity. Users can work interactively at the command line or generate batches from files. Bulk input accepts Rasa NLU training data or CSV rows containing a sentence and optional label; output can use either format and includes similarity scores. Controls cover language, lexical diversity, n-gram penalties, beam search and candidate count. Docker is required, with CPU and GPU container instructions. A lightweight mode is described as about 2.5 times faster, with possible quality impact.
Spec sheet
- Purpose
- It generates paraphrases of sentences that are intended to be semantically similar but lexically and structurally different.Read 4 Oct 2026 · github.com
- Deployment
- The README instructs users to install Docker and documents CPU and GPU container builds and runs.Read 4 Oct 2026 · github.com
- License
- The repository includes an MIT license.Read 4 Oct 2026 · github.com
- Headquarters
- San Francisco, United States, with engineering in Berlin, GermanyRead 28 Sep 2026 · github.com
- Founded
- 2016Read 28 Sep 2026 · github.com
- Content safety
- The README warns that the model can generate offensive content and says the tool does not currently filter or detect it.Read 4 Oct 2026 · github.com
- Feedback
- The README invites users to provide feedback.Read 4 Oct 2026 · github.com
- Generation controls
- Command-line options control language, lexical diversity, n-gram penalization, beam search, and the number of candidate paraphrases.Read 4 Oct 2026 · github.com
- Input formats
- Bulk mode accepts Rasa NLU training data or CSV rows containing a sentence and optional label.Read 4 Oct 2026 · github.com
- Languages
- The model supports 30 languages, but the README says the tool has only been tested in English, German, French, Spanish, and Russian.Read 4 Oct 2026 · github.com
- Model
- It uses a multilingual neural machine translation model from the Prism framework with diversity-promoting decoding changes.Read 4 Oct 2026 · github.com
- Output formats
- Bulk output can use Rasa NLU training data format or CSV, and includes similarity scores for generated paraphrases.Read 4 Oct 2026 · github.com
- Quality option
- A lightweight mode is described as around 2.5 times faster, with a possible negative effect on generation quality.Read 4 Oct 2026 · github.com
- Run modes
- The tool provides interactive command-line use and bulk generation from input files.Read 4 Oct 2026 · github.com
- Use case
- Rasa says it was primarily built for data augmentation inside the Rasa Open Source framework and can also be used for other paraphrasing needs.Read 4 Oct 2026 · github.com
Plans and prices
Strong points and limits
Strong points
- Supports 30 languages
- Interactive and bulk generation
- Rasa NLU and CSV formats
- Similarity scores in bulk output
- MIT-licensed and free
Limits
- Requires Docker
- Testing listed for five languages
- May generate offensive content
- Lightweight mode may reduce quality
Who it suits
It suits developers needing local or self-hosted paraphrase generation, especially for Rasa data augmentation. Users should be comfortable with Docker and command-line workflows.
Verdict
Rasa Paraphraser offers configurable command-line and batch generation with multilingual output and similarity scoring. Its Docker requirement and unfiltered offensive-content warning are important deployment considerations.
Where Specifiction places it
- AI Paraphrasing Tools#16 of 247.7