All three are good tools — they're just built for different jobs. faker is a vast generic-data library; Mockaroo is a schema-builder web app. Sampuli is the one that makes data correct for a specific country and valid against real checksums, with a free API and an MCP server. Here's the honest breakdown.
| Sampuli | faker.js | Mockaroo | |
| Country-accurate ID / tax / bank formats | Yes · 90 countries | Partial | Partial |
| Passes real checksums (IBAN mod-97, Luhn, Verhoeff…) | Yes | No | No |
| Free hosted REST API, no key | Yes | No (library only) | Partial (key + limits) |
| No install (browser · npx · API) | Yes | No (npm only) | Yes (web) |
| MCP server for Claude / Cursor / Copilot | Yes | No | No |
| Reproducible via seed | Yes | Yes | Partial |
| Ready-made KYC / payment scenarios | Yes | No | Partial |
| Rows per run | Unlimited (npm) · 1,000 (API) | Unlimited | 1,000 (free) |
| Huge generic field variety (lorem, avatars…) | Partial | Yes · vast | Yes · large |
| Visual schema builder | Partial (presets) | No | Yes |
| Open source (MIT) | Yes | Yes | No |
| Sampuli | You need data that's correct for a country and passes validators — fintech, KYC, banking, cross-border, compliance testing. Or you want a URL / MCP tool with zero setup. |
| faker.js | You need lots of generic English-ish fields (names, lorem, images) inside a Node app and don't care about country-level validity. |
| Mockaroo | You want to design a bespoke schema in a UI and download a one-off file. |
Want the accuracy detail? See the 57 checksum algorithms Sampuli computes.