Real US mobile numbers, owned and managed in the US by MEISIM USA LLC, a Wyoming company run from Los Angeles.
VoIP numbers fail the number-type checks that apps, banks and fraud stacks run, and their calls arrive as "Spam likely". We give your agent a real mobile number on a national US carrier: texts in and out over an API or a webhook, calls over SIP with the number as caller ID, ordered by API and billed by the month.
Your agent can write code, browse the web and book a table. Then a signup form asks for a phone number, looks up what kind of number it is, and rejects a VoIP one before the code is ever sent. Here is why:
If your product gives an AI a phone, we're the layer that makes it actually work in the real world.
Any voice-agent platform that can register a SIP account. Your agent calls a restaurant for a reservation, and the restaurant sees a real US mobile number, not "Unknown VoIP." You bring your own voice stack; we provide the number and the caller-ID identity.
A companion or character platform gives each companion a real number, bound to the one user who pays for it. The companion texts first, the user answers from the lock screen, and it can call. How it works for companion platforms →
Personal AI that screens your calls, answers spam, schedules with humans. Customer gives the assistant a real MeiSIM number; assistant routes calls, transcribes voicemails, replies via SMS — all behind a number that's indistinguishable from a human's line.
A number your customers will trust — not a 5-digit shortcode or a VoIP line. Inbound SMS on a T-Mobile API line is delivered to your webhook, or polled over the API. Outbound texting is sent from the device the eSIM is installed on; there is no send-SMS API endpoint today.
Authenticated REST, prepaid balance, per-key rate limits. No SDK to install — plain HTTP calls. To read texts from an agent framework, use the MCP tools below.
MeiSIM runs a hosted Model Context Protocol server. Point any MCP-compatible client, Claude, Cursor, Windsurf or your own agent, at one URL with your API key and it can list your numbers, read the texts they receive, wait for the next one, send texts and buy more. No SDK, no polling loop, no glue code.
Tools your agent gets with your API key:
And without a key, the retail tools (travel eSIMs and US plans paid by card):
Open source: github.com/Shauliko/meisimusa-mcp, on npm as meisimusa-mcp. Purchases your agent makes run on your prepaid wallet; a retry with the same reference never orders twice, and the agent cannot add money.
A monthly price per number; usage is billed separately. Two ways to receive: a T-Mobile API line reads its own SMS over the API with webhook push, and a carrier eSIM delivers its texts to the device you install it on.
Plain HTTP and standard SIP, nothing to install. Any agent framework, voice platform or automation tool that can make a request or place a SIP call works as is.
Register the line's SIP credentials; the number rings your agent
A function tool that buys a number and reads its texts
One number per companion, bound to its user
The agent's own user confirms a number the agent holds
Python + JS tool definitions
Every inbound text pushed to your URL, signed
No-code automation nodes
For Claude Desktop, Cursor, Zed
For pure voice agents that only call humans (booking, support), a VoIP number is fine. The problem is two-way SMS: a signup or a bank looks up the number type and refuses VoIP before the code is sent, and a VoIP caller ID arrives labelled. A real mobile number passes both.
From API call to active eSIM ready for use: typically 8–25 seconds for AT&T retail, 30–90 seconds for MobileX/T-Mobile depending on carrier load. We pool inventory in advance so you're not waiting for carrier-side provisioning on every request.
Yes. The Scale tier includes a bulk API endpoint that returns up to 1,000 numbers in a single async job. Useful when a platform gives every one of its users or agents a number of their own.
Two products, and the difference is where the SIM physically is.
T-Mobile API line — a real T-Mobile number, and we receive its SMS. The SIM lives in a gateway rather than in a handset, so the message reaches us and we pass it on: webhook push to your URL (POST /api/v1/sms/webhook to set it, HMAC-signed as X-MeiSIM-Signature) with GET /api/v1/sms/messages as the record behind it. A real carrier number that your code can read is the combination most stacks cannot offer.
Carrier eSIM — you install it on a device, and its texts go to that handset. Not to us, and no provider can change that; it is how a SIM works. Right for a phone somebody uses, wrong for code that needs to read the message.
T-Mobile API line with voice: yes, both directions, over SIP. Each line gets its own SIP credentials (host, port, user, password); register them from any voice-AI platform, PBX or softphone, and the number rings your agent. Outbound shows the line's own number, a real mobile. Usage is billed separately from a prepaid balance, and each line carries one call at a time, so ten simultaneous calls means ten lines.
Carrier eSIM: calls ring the handset it is installed on, like any phone.
The rule that comes with it: a line used for robocalling, unsolicited calls or texts, or verification fraud is blocked the moment we see it and the account is closed for good, no warning, no refund. Legitimate agents never notice this rule exists.
Credit/debit (Stripe), PayPal, Apple Pay, Google Pay, USDT crypto (TRC20 + ERC20), Alipay, WeChat Pay. We deliberately accept crypto because a lot of our AI-agent customers are international startups that struggle with US payment rails.
Indie tier: best-effort. Growth: 99.5% number-active SLA + 4h support response. Scale: 99.9% SLA + 1h response + dedicated Slack channel.
Carriers occasionally deactivate prepaid lines for inactivity, suspected fraud, or quota issues. We monitor and replace automatically on Growth and Scale tiers — we notify you and issue the replacement. There is no automatic in-flight SMS forwarding — a code sent to the old number in that window is lost, so re-request it after the swap.
Prepaid, by card, crypto, wire or Zelle, from a single number up. Apply, a person approves the account (usually the same day), the API key arrives with the approval, and you can be in production the same afternoon.
Apply for API access →Every account agrees to the API and lines terms: one-to-one use, no bulk traffic, KYC on every buyer.