A Flipper Zero app that reads and decodes Belgian MOBIB transit cards — the Calypso/ISO 14443-B contactless card shared by STIB/MIVB, SNCB/NMBS, De Lijn and TEC.

Tap any MOBIB card against the Flipper's back and the app identifies it, dumps every readable file, decodes the human-meaningful fields and saves the capture to the SD card so you can browse it again later without the card.

Every scan is auto-saved to /ext/apps_data/mobib/dumps/<PUPI>_<UTC>.mobibdump as a human-readable FlipperFormat file. Use Saved cards from the main menu to re-render any past capture without a card present.

Writes are impossible without the issuer's keys. Calypso writes (UPDATE RECORD, INCREASE, DECREASE) require an authenticated Secure Session opened with a 3DES/AES key held in a hardware SAM that only transit operators possess. This app is read-only by design and cannot:

• Forge, modify or top up contracts
• Increment/decrement remaining-trip counters
• Decrypt the card's MAC authenticators
• Read files whose access conditions demand an open Secure Session

If someone offers you a Flipper app that "writes MOBIB", it is either a scam or is misusing a leaked operator key — neither will survive contact with an actual fare gate.

Target firmware: Momentum via ufbt.

ufbt            # build the .fap into dist/
ufbt launch     # build, upload to a connected Flipper and launch
ufbt cli        # open a serial CLI to the device

The built dist/mobib.fap can also be copied manually to /ext/apps/NFC/ on the SD card.

application/
  calypso/         APDU layer, BER-TLV walker, record decoders
                   (FCI, env, event, contract, holder, stations, bus)
  nfc/             Iso14443_4b poller wrapper + full-card dump
  storage/         FlipperFormat persistence (save + load)
  ui/              Section formatters (Overview/Holder/…/Deep scan)
  scenes/          Scene Manager scenes (start, scan, card, etc.)
docs/              Design notes + MOBIB protocol references
samples/           Git-ignored local .mobibdump captures
icons/             App icon (10x10 PNG, 1-bit)
application.fam    FAP manifest consumed by ufbt

The app ships field layouts, station tables and alphabet rules ported from two excellent open-source projects. They did the hard work; this is a re-expression of their findings in a form the Flipper Zero firmware can run:

• metrodroid/metrodroid — Kotlin/Android transit reader. Source of MOBIB environment, event, contract and holder bit layouts; of the Calypso file map (CalypsoApplication.kt); of the 5-bit name alphabet. GPL-3.0.
• zoobab/mobib-extractor — 2009-era Python MOBIB decoder. Source of the STIB metro station table (70 rows) and bus stop database (~2200 rows) compiled into calypso_stations.c / calypso_bus.c.
• Intercode v2 / Calypso public specifications.

When STIB renumbers a stop or adds a new one, regenerate the tables from the upstream CSVs:

python3 <<'PY'
import csv
with open('zoobab-data/Database/Metro.csv') as f:
    r = csv.reader(f); next(r)
    for row in r:
        _, zone, sz, st, line, name, *_ = [c.strip() for c in row]
        print(f'{{0x{int(zone,2):02X}, 0x{int(sz,2):X}, 0x{int(st,2):02X}, "{line}", "{name}"}},')
PY

The bus table uses the same CSV with line/code columns and is kept sorted on (line, code) for binary search.

GPL-3.0-or-later. See LICENSE.

Not affiliated with STIB/MIVB, SNCB/NMBS, De Lijn, TEC, Calypso Networks Association, or any transit operator. Exists for interoperability research and for reading your own cards. Respect your local laws around RFID and personal data.