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SIM Types

All Telnyx SIMs are eUICC-enabled. Three form factors:

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Resource Model

Three core resources, all API-managed:
  • SIM Card — the connectivity entity. Has an ICCID, status, data settings, optional voice flag. Covers both physical SIMs and eSIMs (eSIMs are purchased via a separate endpoint but become the same SIM Card resource with an activation code for OTA provisioning). Everything starts here.
  • SIM Card Group — bulk management. Apply data limits, network preferences, and Private Wireless Gateway configs to all SIMs in a group at once.
  • Mobile Phone Number — optional. Created when you enable voice or messaging on a SIM. Controls call forwarding, caller ID, messaging profile.

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SIM Lifecycle

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Multi-IMSI

Every Telnyx SIM carries multiple IMSIs (Telnyx, Sparkle, BICs, T-Mobile, US Cellular). An on-SIM applet automatically selects the best IMSI per location — local network attachment instead of roaming, lower latency, better rates. Default is automatic selection. You can override to manual per-SIM or per-group via API if you need to pin a specific IMSI for regulatory or testing purposes.

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Pricing

Three cost components: