Brazilian RG Generator

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Synthetic Brazilian RG SSP/SP for test fixtures

Synthetic SSP/SP RG for test fixtures

Every RG fixture needs a plausible value without touching a real identity. This site's RG generator implements the SSP/SP rule: an 8-digit base plus 1 modulo-11 check digit, which can end in X. This page shows how to pin the seed, read the deterministic value and guard the field mask against that trailing X.

What an RG fixture needs to know about the generator

The synthetic value has exactly 9 core characters: an 8-digit base followed by the check digit, displayed with SSP/SP punctuation as XX.XXX.XXX-D. Before returning the result, the generator discards repeated sequences, like 11111111 or 99999999, using a filter that rejects any string where the same digit repeats from start to end. It tries up to 20 random bases under that condition; if every one lands on a repeat, it falls back to the fixed base 12345678, which closes with check digit 2, producing 12.345.678-2. A fixture that calls the function in a loop should account for that 20-attempt ceiling.
For CI reproducibility, the function accepts a custom digit source instead of the default random generator: a fixed sequence like 7, 4, 1, 0, 5, 9, 2, 3 replayed in the same order always produces the same RG, in this case 74.105.923-X. That lets you write a contract test that compares the generated value against a fixed result, without relying on luck to never land on a repeated sequence. You can also skip random generation entirely and call the function that takes the base directly, which is faster for a fixture that only needs one fixed value reused across hundreds of test cases.
The detail that most often breaks a fixture is the X check digit: it shows up whenever the remainder of the division by 11 is exactly 1, which happens in roughly one out of every eleven generated values. A form mask written with only digits in the last position rejects that valid RG and makes the test fail intermittently, since the value changes on every run without a fixed seed. The fix is to accept a digit or X in the last character, both in the validation regex and in the text field used by the staging form, and to explicitly test one case with X and one without.

Three synthetic RGs, three fixture checks

Deterministic seed 74105923

Input: 7,4,1,0,5,9,2,3 → generateRg(source)
Expected output: 74.105.923-X

The same digit sequence, replayed from the start, always ends in X because the weighted sum of base 74105923 leaves remainder 1 when divided by 11.

Fallback with no seed (20 attempts exhausted)

Input: createRgFromBase('12345678')
Expected output: 12.345.678-2

This is the fixed value the function returns when all 20 random attempts land on a repeated sequence; useful as a test constant that never changes between runs.

Zeroed base, digit becomes 0

Input: createRgFromBase('00000000')
Expected output: 00.000.000-0

When the remainder of the division by 11 is 0, the computed digit would be 11, and the function substitutes it with 0; the fixture needs to accept an RG of nine consecutive zeros as a valid value.

Full tool FAQ

Does RG have national validation like CPF?

No. The RG is issued by state agencies and there is no single national algorithm comparable to the CPF's. Each Public Security Secretariat uses its own format and rule, so a number valid in one state may make no sense in another.

Does this RG pass in any system?

Is the check digit really calculated?

Does the generated RG belong to someone?

Why does the tool show SSP/SP?

Can I use it in automated tests?

Is the number sent to a server?

When should I not use this generator?

Frequently asked questions

How do I pin the seed of a synthetic RG for a contract test?

Replace the default digit source with a function that always returns the same sequence, or call the function that takes the 8-digit base directly, skipping the random step entirely; either approach guarantees the same RG on every CI run.

Why does my mask regex reject a valid synthetic RG?

Because the last position of an SSP/SP RG can be the letter X, not only a digit; a regex written with digits only, without including X, drops roughly one in every eleven generated values, a classic fixture bug that only shows up intermittently.

Can the generator return two identical synthetic RGs in the same test suite?

Yes, without a deterministic seed the generator does not guarantee uniqueness across calls: it only filters out repeated-digit sequences, not collisions against values already emitted. A suite that needs distinct RGs has to enforce that in the fixture itself, not assume the function handles it.

Does a synthetic RG generated here pass an official identity lookup?

No, and it should never be treated as one outside an isolated test environment: the calculation only reproduces the SSP/SP format and check digit, without querying any real identity database, live or otherwise.

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Synthetic Brazilian RG SSP/SP for test fixtures

Synthetic SSP/SP RG for test fixtures

What an RG fixture needs to know about the generator

The synthetic value has exactly 9 core characters: an 8-digit base followed by the check digit, displayed with SSP/SP punctuation as XX.XXX.XXX-D. Before returning the result, the generator discards repeated sequences, like 11111111 or 99999999, using a filter that rejects any string where the same digit repeats from start to end. It tries up to 20 random bases under that condition; if every one lands on a repeat, it falls back to the fixed base 12345678, which closes with check digit 2, producing 12.345.678-2. A fixture that calls the function in a loop should account for that 20-attempt ceiling.

For CI reproducibility, the function accepts a custom digit source instead of the default random generator: a fixed sequence like 7, 4, 1, 0, 5, 9, 2, 3 replayed in the same order always produces the same RG, in this case 74.105.923-X. That lets you write a contract test that compares the generated value against a fixed result, without relying on luck to never land on a repeated sequence. You can also skip random generation entirely and call the function that takes the base directly, which is faster for a fixture that only needs one fixed value reused across hundreds of test cases.

The detail that most often breaks a fixture is the X check digit: it shows up whenever the remainder of the division by 11 is exactly 1, which happens in roughly one out of every eleven generated values. A form mask written with only digits in the last position rejects that valid RG and makes the test fail intermittently, since the value changes on every run without a fixed seed. The fix is to accept a digit or X in the last character, both in the validation regex and in the text field used by the staging form, and to explicitly test one case with X and one without.

Three synthetic RGs, three fixture checks

Deterministic seed 74105923

Input: 7,4,1,0,5,9,2,3 → generateRg(source)
Expected output: 74.105.923-X

The same digit sequence, replayed from the start, always ends in X because the weighted sum of base 74105923 leaves remainder 1 when divided by 11.

Fallback with no seed (20 attempts exhausted)

Input: createRgFromBase('12345678')
Expected output: 12.345.678-2

This is the fixed value the function returns when all 20 random attempts land on a repeated sequence; useful as a test constant that never changes between runs.

Zeroed base, digit becomes 0

Input: createRgFromBase('00000000')
Expected output: 00.000.000-0

When the remainder of the division by 11 is 0, the computed digit would be 11, and the function substitutes it with 0; the fixture needs to accept an RG of nine consecutive zeros as a valid value.

Full tool FAQ

Does RG have national validation like CPF?

Does this RG pass in any system?

Is the check digit really calculated?

Does the generated RG belong to someone?

Why does the tool show SSP/SP?

Can I use it in automated tests?

Is the number sent to a server?

When should I not use this generator?

Frequently asked questions