Methodology, sources and catalog changelog

How a result is built

1. The selected profile supplies one eight-digit prefix from the versioned local snapshot.
2. The server adds a cryptographically generated six-digit testing serial.
3. The fifteenth digit is calculated with the Luhn formula used for IMEI check digits.
4. The service rejects repeats inside the current batch and returns at most 50 rows.

Passing Luhn proves only that the number is structurally valid. It does not prove that a device exists, that a TAC-to-model mapping is current, or that a number is absent from carrier and GSMA systems.

TAC data scope

The bundled mappings are an internal fixture set migrated from earlier application code. Their original upstream provenance and reuse license are not established, so Random IMEI does not publish the raw mappings as a reusable dataset. Current labels are test labels, not device claims, and are not sent to the browser validator, which performs no device attribution.

Random IMEI is not affiliated with or endorsed by GSMA, does not redistribute the licensed GSMA Device Database, and does not claim real-time, complete, or authoritative coverage.

A generated serial can theoretically coincide with an assigned device identifier. Use outputs only as synthetic fixture data in isolated test environments; never submit them to carrier, activation, warranty, financing, insurance, blacklist, or production identity systems.

Who writes the content and how it is reviewed

David Santacruz writes and maintains the application and its guides. Each guide shows when it was published and last updated, lists its sources and records corrections in its changelog.

Format explanations are compared with primary specifications. Device-specific instructions link to manufacturer sources, and model-to-prefix labels carry no device claim unless supporting evidence is recorded. For software behavior, review uses explicit input and output checks: lengths, ASCII digits, Luhn results, leading zeros and exports. These checks exercise software; they do not test physical phones or query a device registry.

The CSV QA lab publishes the sample inputs, expected report and runnable project together. It includes negative and duplicate cases that the normal generator does not produce. Run it locally to inspect each result, then compare the same values with the browser validator. The project documents its runtime and commands.

Primary technical references

• ETSI TS 123 003 V16.11.1, Annex B — the IMEI check-digit calculation. For a 14-digit body, double positions 2, 4, 6, 8, 10, 12 and 14 counting from the left.
• GSMA IMEI Database overview — the three IMEI parts and GSMA TAC allocation role.
• GSMA TS.06 IMEI Allocation and Approval Process — current allocation principles, duplication prevention and security requirements.
• GSMA security FAQ — concise definitions of TAC and IMEI.

What the validator checks

The validator normalizes the input, distinguishes a completable 14-digit body from a complete 15-digit IMEI, and calculates or checks the Luhn digit entirely in the browser. It extracts the first eight digits as the TAC field but does not compare them with the internal generator snapshot or attribute a manufacturer or model. It does not query GSMA, a carrier, a blocklist, a manufacturer, warranty records, ownership records, or live device status.

Changelog

1. 2026-10-09 — Reworded data scope and caveats. Shortened repeated caveats on this page and on the developer resources page, and explained the origin of the TAC data once, in the data scope section above. No mapping or generator changes.
2. 2026-09-09 — Test profiles, runnable examples and editorial corrections. Named the site operator and clarified the historical editorial byline. Reworded selectors and results as test profiles, connected the generator to a runnable CSV validation example, and separated the Apple and Samsung inventory tasks. Revised the ten-device guide pilot around documented SIM and identifier differences. Corrected the iPhone guide's Luhn instructions in English, Spanish, French and Portuguese; removed the cheat-sheet promise of a manufacturer TAC table. Made the email-app handoff explicit and described the actual regional consent defaults. No new TAC mappings were added or verified in this revision.
3. 2026-08-05 — Canonicalization and provenance boundary. Consolidated generator TAC data in one versioned server-only snapshot, made every legacy mapping explicitly unverified, removed catalog lookup from browser validation, and published only the independently authored CC0 Luhn vectors as reusable data.
4. 2026-07-18 — Transparency revision. Published this methodology, clarified collision and coverage limitations, and aligned site claims with the actual 50-row server-side generator. No TAC mappings were added in this revision.
5. 2025-11-02 — Catalog snapshot. Last recorded change to the server-side device/TAC catalog.

Corrections

To report an incorrect mapping or documentation issue, email support@randomimei.com. Include the affected profile and a link to a reliable source. Reports are reviewed manually; submission does not guarantee inclusion.