Developers
Use it for seeds, mocks, and API samples. A CPF with modulo-11 digits passes a front-end check; a UUID v4 becomes a fixture id; a sample JWT shows the claims before you connect a real provider.
Ontoom
Online generators and validators for testing
CPF, CNPJ, IBAN, SSN, VAT, QR codes and more — free in the browser, no sign-up. Synthetic data for developers and QA.
Ontoom brings together generators, validators, and utilities that run in your browser for software testing, staging, and study. Below is what the site is, who it is for, what it is not, and how to use a result without turning it into a document.
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30 tools
What Ontoom is
Ontoom is a free toolkit for people who fill forms, build fixtures, and inspect formats all day. Instead of reusing a real customer’s data in a test environment, you generate a synthetic value with the right mask and, on the same page, read what that value means.
The catalog covers Brazilian test documents (CPF, CNPJ, RG, and a person generator), codes (QR, barcodes, digitable lines, OCR), international references (IBAN, SSN, VAT), and developer utilities (JWT, Base64, JSON, cURL, HTTP status). There is also a Pomodoro timer and simple calculators. Each item opens a page with the control and an explanation, not only a link.
No account is required. The About page says who runs the site; Contact is the channel for bugs and privacy; Privacy and Terms describe data and allowed use.
Who it is for
QA and staging
Build scenarios without production PII: a numeric CNPJ, a sample boleto, an IBAN with a checksum, a QR code for a staging URL. The goal is for the app to react to the format, not to simulate an identity.
Students
The pages explain the math next to the button. You can study masks, check digits, the difference between Base64 and secrecy, and the HTTP status table with what each range means.
What Ontoom is not
Ontoom is not Brazil’s tax authority, does not query an official registry, and does not issue documents. A generated CPF or CNPJ can have correct check digits and still not exist as a person or company record. Mathematical validity is not permission to use the number in the real world.
Do not use the results for fraud, account opening, invoices, contracts, or impersonation. That is forbidden by the Terms of Use and may be a crime. Test data stays in a test environment. If you need a real document, stop and use the competent agency.
How to use the tools
The flow is the same across most of the catalog. Four steps avoid the most common and most dangerous mistake: treating a test number as a document.
- 1
Pick a tool
Use search, shortcuts, or the categories on this page. The card summarizes the job; the tool page explains format, options, and limits.
- 2
Generate or validate in the browser
Set the mask, quantity, or QR text and press the button. The calculation happens on your device. Copy the result next.
- 3
Use it only for testing and study
Paste it into a fixture, a staging form, or an exercise. Do not publish the value as if it were a real person’s document.
- 4
Check the context
CPF and CNPJ have a validator on the tool or on a neighboring page. The blog and each page’s text describe the algorithm when it changes how you should test.
Featured tools
Six pages cover most of the use. Each one has its own text about the format and what the result does not prove.
CPF generator
Builds numbers with both modulo-11 check digits, with or without a mask. Use it to test inputs, form validation, and sign-up seeds. The page is clear that “valid” here means the math checks out, not that the number is registered, and it links to the validator for a number you already have.
Open the CPF generatorCNPJ generator
Produces a numeric CNPJ with the right digits, with or without the 00.000.000/0001-00 punctuation. Product teams use it for company sign-up, sample boletos, and B2B checkout. The result is synthetic: the tool does not query the tax registry and does not prove a company exists.
Open the CNPJ generatorQR code generator
Turns a URL, text, Wi-Fi network, email, or phone number into an image you can download immediately, with adjustable size and error correction. Dynamic QR, on the neighboring page, stores destination, status, and expiry in your browser so you can change the link without reprinting the artwork.
Open the QR code generatorBase64
Encodes and decodes text and files in the browser, with a preview when the content is an image. Use it to inspect a data URI or a payload without uploading the file. The page treats Base64 as encoding: anyone who sees the string can reverse it, so it is not secrecy.
Open the Base64 toolJWT
Splits header, payload, and signature so you can read the claims. With an HS256 secret you can check the signature locally and mint a sample token. The token you paste is not sent to Ontoom; the tool does not replace your production identity provider.
Open the JWT toolPerson generator
In one click, builds a fictional pack for a long form: name, CPF, RG, driver’s license, address, and sample contacts. It is the shortcut when a staging sign-up needs every field. No field points at a real person; the tool page describes each block.
Open the person generatorCommon questions
- Is a generated CPF a real person?
- No. It follows modulo 11 and may pass a form check, but it is not looked up at the tax authority and it does not represent a registry record. Use it only for testing and study.
- Does Ontoom upload what I generate?
- Not because you used the tool. The calculation stays in the browser. The contact form, analytics, and ads are a separate flow, described in the privacy policy.
- Can I use the number to open an account or issue an invoice?
- No. That use is forbidden and may be fraud. The terms limit the result to testing, staging, and learning.
- Do I need an account?
- Not to use the tools. Search, generation, and validation work without sign-up. Favorites are stored in this browser.