[ 10 / comparison — test data ]
Synthaveil and synthetic test-data tools.
What it is
Tools that build a synthetic copy of a dataset, usually as a scheduled job against a database, so development and test environments can run on data shaped like production without holding production.
Where it wins
For filling a test database overnight, these are purpose-built and better at it than we are. Several also model joint distributions more thoroughly than we do. We are not trying to replace them.
Where we differ
Choose based on the task: generating a test dataset, substituting fields in a live workflow or preparing a prompt. Recovery is product-specific; generated synthetic records need not correspond to an original person.
| Capability | Synthaveilthis site | Test dataBatch generation |
|---|---|---|
| Runs inside your own environment | yes | yes |
| No generative AI or large language model reads your real data | yes | partly |
| Output keeps its shape — a name looks like a name, a date like a date | yes | yes |
| Consistent results without a stored table of real-to-fake values | yes | partly |
| Nothing held at the vendor that could reverse it | yes | yes |
| Replacement matched on statistical character, not only on format | yes | yes |
| Location stand-ins that keep the area useful without pointing back to it | yes | not verified |
| Stand-ins go stale on a schedule | yes | not applicable |
| Reversible on your side when you need the real value back | yes | not verified |
| An audit record for every policy decision | yes | partly |
| Works on live traffic, not only batch jobs | yes | not verified |
| Word, Excel and browser add-ins | yes | not verified |
| Stand-ins built from official public statistics | yes | partly |
| Detection across many languages and file types | partly | not applicable |
| Free to use | no | not verified |
Source: Synthetic Data Vault project
Can the stand-in values be turned back into the real values?
Yes, on your side. When an AI tool replies using stand-ins, Synthaveil puts the real values back, so the answer reads with your real names and is ready to use. Alias, Cover and Legend all restore values; each product page sets out how.
Is pseudonymised data still personal data under GDPR?
For you, yes: you hold the key, so it remains personal data in your hands. The EU Court of Justice (EDPS v SRB, 2025) and the ICO (2025) both look at whose hands the data is in: a recipient with no key, no mapping and no other route to the person may not hold personal data at all. That is what Synthaveil sends an AI provider: stand-ins with no route back. Your duty to tell people about the sharing still applies when you collect their data.
Does Synthaveil make my data anonymous?
No. Synthaveil makes no claim that its output is anonymous. In your hands it remains personal data, because you hold the key. What changes is what the recipient gets: stand-ins with no key or mapping to link them back. Review the remaining context before you share.
Do you have to store a mapping table to keep pseudonyms consistent?
No. Synthaveil keeps stand-ins consistent without storing any real-to-stand-in pairs. Products that restore values keep that information on your side, in your browser, workbook or n8n environment, and it needs protecting.