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esimker MCP server

Which MCP servers are esimker's own, from the official registry and from asking its own domain, whether they answer, and what they offer. A program checked each of these, nobody copied them from a product page.

read 2026-10-24

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Whose server it is
  • Registry namecom.esimker/esimverified in the MCP registry

The registry name sits under esimker.com. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

When we asked itchecked 2026-10-24
  • Stateanswerschecked 2026-10-24
  • Tools12
  • Server calls itselfesimker
  • Server version2
  • Protocol version2025-06-18

On 2026-10-24 the server answered initialize and tools/list without a sign-in. First answer in 222 ms.

Should an agent connect itNot proven either way yet
  • Its tools do Buy a data pack for a trip abroad; Top up an existing esim with more data, but not Install an esim on a compatible phone.
  • Checked on 3 of the 7 days it takes to judge reliability.

Once connected

  • For "Buy a data pack for a trip abroad", the likely first call is search_destinations.
  • For "Top up an existing esim with more data", the likely first call is list_topups.
  • create_checkout, create_wallet, create_deposit change data without a sign-in: anyone with the address can call them.
  • Parameters are untyped or undescribed in 10 of 12 tools: check arguments before calling.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

Measured dailydaily checks: 3, the first on 2026-10-24
  • INITE MCP scoreafter a weeka score needs 7 daily checks: 3 so far
  • What an agent can do with it2 of 3 use cases
  • Answeredmeasuring3 of the 7 daily checks it takes to print a share
  • Median first answer644 ms
  • Space in an agent's context≈ 2,174 tokensthe definitions of all its tools (12), which an agent carries on every turn
  • Tool definitionsB · 86 of 100
  • Typed results12 of 12 toolsdeclared outputSchema: results come typed, read once
  • Parameters without a description: in 10 of 12

What an agent can do with it

  • can do · Buy a data pack for a trip abroad
  • cannot · Install an esim on a compatible phone
  • can do · Top up an existing esim with more data

Each of the product's use cases, put to Jev against this server's tool list: can an agent do it with these tools?

Worth a look

  • Tools that change data, on a server that answers without a sign-in: create_checkout, create_wallet, create_deposit

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (25%), doing the product's job (25%), definitions (20%), context (10%), use (10%) and how readily a client connects (10%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

Tools it offers12 tools · read 2026-10-24
  • search_destinations

    Destinations on sale. `query` matches the name in any of 18 languages, the slug or the ISO code; empty lists everything. Each item: dest_code, slug, name, min_retail (USD, the cheapest fixed plan), unlimited_from (USD per day of a Daily…

  • get_plans

    The plans of one destination (slug from search_destinations). Each plan: id (the plan_id for an order), name, gb, days, retail (USD; per day when daily_unlimited is true), daily_unlimited, location_codes (the countries it covers)…

  • get_payment_methods

    Checkout methods open right now: "crypto" (a hosted invoice: BTC, ETH, TRX, USDT), "card", and "wallet" (a prepaid balance, see create_wallet). `gateways` names the providers behind each method; a checkout that does not ask for one by…

  • create_checkout

    Create an order for a person to pay. Returns token, checkout_url (the gateway's page: hand it to the person) and order_url (the order page in `lang`, with the QR code once paid: show it to the buyer only, the token is a secret). Confirm…

  • get_order

    An order by its token. status goes pending (unpaid) → paid → provisioning → ready; also expired, underpaid, failed_provisioning, gift_waiting, and payment_held — the payment processor's compliance check stopped the payment and holds the…

  • list_topups

    Top-up plans that fit an eSIM we issued: plan_id, name, gb, days, retail. Order one with create_checkout(plan_id, topup_iccid=iccid) or, from a wallet, purchase_esim(plan_id, client_ref, topup_iccid=iccid).

  • get_usage

    Remaining data and status of an eSIM we issued.

  • create_wallet

    Mint a prepaid wallet with no account behind it and get its secret ONCE: `code` (32 hex characters) and the same secret as a 12-word `phrase`. Save the code before doing anything else and send it as `Authorization: Bearer <code>` on every…

  • get_wallet

    The wallet behind the code: ref (a public handle for support), balance_usd, cashback_percent, the deposit rules that apply to it now (min_usd, max_usd, first, bonus tiers), the last 50 transactions, orders (with their tokens — the wallet…

  • create_deposit

    Open a top-up of the wallet and get what is needed to pay it. Floors: $10 for a wallet's first deposit, $1 after that; cap $1000 per deposit. Crypto deposits earn a bonus (+2% from $25, +3% from $50, +5% from $100, capped at $25); every…

  • get_deposit

    One deposit of the wallet by its token: status pending → paid (credited, bonus included) | underpaid (nothing credited yet, the rest can still arrive) | payment_held (the payment processor's compliance check stopped the payment and holds…

  • purchase_esim

    Charge the wallet and issue an eSIM, no checkout. `client_ref` (1–64 chars) is your own reference for this purchase and makes the call idempotent: a retry with the same value returns the existing order without a second charge, so reuse it…

How to connect

Add the server to your MCP client config. Claude Desktop, Cursor and most other clients read this shape:

{
  "mcpServers": {
    "esim": {
      "type": "http",
      "url": "https://esimker.com/api/mcp"
    }
  }
}

Add it

Claude Code, in a terminal

claude mcp add --transport http esimker https://esimker.com/api/mcp

Add to CursorAdd to VS Code

claude.ai, ChatGPT and other clients: add https://esimker.com/api/mcp as a custom connector in the settings.

Each line is something a program found when it went looking: the registry entry, the server's own answer, a spec that parses. A missing line means we did not find it, not that it does not exist.