eSIM & Agent-Native Connectivity Glossary
Plain-language definitions for the terms this category runs on — from per-MB metered billing to x402 machine payments. Each definition is one quotable answer followed by the context that makes it precise.
Per-MB (metered) eSIM
An eSIM billed per megabyte from a prepaid balance instead of sold as a fixed data package: 180 MB used means 180 MB billed, with no bundle to size and no validity window. Also called usage-based or pay-as-you-go billing — the meter runs only while data flows.
Breakage
The unused portion of a prepaid data package that is forfeited when its validity window closes — the hidden margin of package eSIMs. A typical traveler buying 5 GB for a week and using 2 GB loses 60% of what they paid for; metered billing eliminates breakage entirely.
No-KYC eSIM
A data eSIM that can be purchased and activated without identity verification — no passport upload, no registration. Contrast with local SIM laws in Germany, Turkey, India, Indonesia and others that mandate registering every SIM to a verified identity.
Anonymous-first (anon-first)
A service model where a working account exists before any signup: connect, use, pay — identity optional. Roamzy applies it to connectivity: the MCP server creates an anonymous account on first use, and it can later be claimed with a login without losing anything.
Data-only eSIM
An eSIM that provides internet access but has no phone number — it cannot make calls or send/receive SMS. Practical consequence: WhatsApp keeps working (it binds to your number, not your SIM), but bank OTP texts still arrive on your home SIM, which should stay installed.
eUICC (eSIM chip)
The embedded, reprogrammable SIM chip soldered into a device, capable of storing multiple carrier profiles. It is what makes an eSIM an eSIM: profiles are downloaded over the air instead of shipped as plastic.
EID
The eUICC Identifier — a 32-digit serial number unique to a device’s eSIM chip. Dialing *#06# shows it; if an EID line appears, the phone supports eSIM.
LPA / activation code
The string (LPA:1$smdp.example.com$CODE) that tells a phone where to download an eSIM profile — the QR code on an eSIM voucher is this string encoded as an image. iOS 17.4+ can also consume it directly as a tappable link, skipping the QR scan.
Agent-native connectivity
Connectivity a software agent can buy and manage end-to-end with no human-only steps: machine-readable pricing, API or MCP purchase flow, programmatic activation and top-up. Distinct from merely "having an API" — every step from price discovery to a working eSIM must be completable by the agent.
MCP (Model Context Protocol)
An open protocol that lets AI assistants call external tools and services in a structured way. Roamzy exposes 12 MCP tools (rates, estimates, purchase, activation, referral) so assistants like Claude can provision an eSIM inside a conversation.
x402
A machine-payment standard that revives the HTTP 402 "Payment Required" status code: a server quotes a price in a header, the client settles a stablecoin micropayment, and retries the request with proof of payment. It targets exactly the agent-pays-for-a-resource loop that human checkout flows cannot serve.
Agentic commerce
Transactions initiated and completed by AI agents on behalf of users — researching, choosing, paying and provisioning without a human at the keyboard. Connectivity is a canonical first category: metered, digital, low-stakes and needed by agents themselves.
RLAH (Roam Like At Home)
The EU rule letting EU-plan holders roam inside the EU at domestic prices. It helps only EU residents inside the EU — visitors from the US, Asia or the UK post-Brexit, and any EU traveler outside the zone (Turkey, Switzerland), still pay full roaming and are the natural travel-eSIM audience.
Sources & further reading
Live per-country rates: prices and the data price index. Setup: install guides. For AI agents: agent-native overview.