Semantic types

A type declares the semantics of a column so Brume knows what kind of value to generate. Types apply only to the FAKE and MASK strategies — other strategies don’t need them.

Available types

Type	Strategy	Example output (FAKE)	Example output (MASK)
EMAIL	FAKE	alice.smith@example.com	a***@e***.com
FIRST_NAME	FAKE	Alice	A****
LAST_NAME	FAKE	Dupont	D*****
PHONE	FAKE · MASK	+33 6 12 34 56 78	+33 6 ** ** ** 78
ADDRESS	FAKE · MASK	12 rue de la Paix, 75002 Paris	** rue ************, 75002 Paris
IBAN	FAKE · MASK	FR76 3000 6000 0112 3456 7890 189	FR76 **** **** **** **** **** 189
IP_ADDRESS	FAKE · MASK	192.168.1.42	192.168.*.*
JSONB	FAKE	(delegated to json_paths)	—

Notes per type

EMAIL

Generates a syntactically valid email using a fake first name + last name + a safe demonstration TLD. Stable across runs for the same input + secret.

FIRST_NAME · LAST_NAME

Picks from the Datafaker dataset matching the system locale, seeded by HMAC. To get cross-table consistency (the same real person → the same fake first name in users and payments), declare a linked_columns entry.

PHONE

Generates a phone number in the locale format. MASK keeps the international prefix and the last digits, replaces the middle.

ADDRESS

Generates a street, postal code, city. MASK keeps the postal code and city, masks the street number and name.

IBAN

Generates a syntactically valid IBAN (correct country code and check digits). MASK keeps the country / check / last block, masks the rest.

IP_ADDRESS

Generates an IPv4 address. MASK keeps the first two octets (network), masks the last two (host).

JSONB

Special type: indicates that the column is a JSONB document and Brume should delegate to the json_paths declaration to anonymize specific fields inside the document. See the JSONB recipe.

Choosing a type

Pick the type that matches the column semantics, not its Postgres type. A VARCHAR(255) storing IBANs needs type: IBAN, not “any string”.

If your column doesn’t fit any semantic type but you still want a deterministic fake string, prefer HASH — it gives you a stable opaque value without trying to mimic a real format.

Next

• brume.yml reference — full configuration schema.
• Pseudonymization strategies — what each strategy does.