GSM/SIM & eSIM tools, decoded properly.
Reference-grade, 100% client-side decoders for practitioners who actually read EF_ICCID off a card — plus senior SIM/USIM/OTA consulting, applet development and eSIM advisory. Built by a specialist with 20+ years across SIM, OTA platforms and applets. EN/PT.
The tools
Each cites the governing spec (ITU-T, ISO 7816, ETSI TS 102 221, 3GPP TS 31.102, GSMA SGP.22). Deep-linkable and free.
ICCID Parser
Luhn validate + generate, with the EF_ICCID BCD view.
IMSI Parser
MCC/MNC/MSIN with the 2-vs-3-digit MNC resolved.
APDU Decoder
ISO 7816-4, SIM/UICC-native, status words.
File-System Reference
Interactive MF/DF/EF tree with per-EF decoders.
eUICC EID Parser
Decode a 32-digit EID; separate EID from ICCID.
Activation-Code Decoder
Split an SGP.22 LPA string field by field.
Work with a senior specialist
A senior-only boutique, not implied headcount. Deep specialist help across the classic-SIM world and the eSIM/eUICC transition.
SIM / USIM Consulting
File-system design, provisioning, interop debugging, RFP support.
OTA Platform Work
TS 102 225/226 secured provisioning, KIc/KID/TAR, SMSC integration.
SIM Applet Development
Java Card / STK / CAT, GlobalPlatform, spec to deployment.
Operator & eSIM Advisory
SIM→eSIM roadmaps, RSP architecture, technical diligence.
SIM Explorer — read any card on your PC
Free desktop companion: read a card via any PC/SC reader, browse the full file system, decode every standard file. Pro adds write, batch and eSIM workflows.
Latest briefs
Practitioner-grade explainers on classic SIM and the eSIM transition.