Issue travel eSIMs from your own product.
One HTTP call returns an activation code, a ready-made QR image and install links for your customer. Wholesale pricing in US dollars, prepaid credit, and a sandbox you can use the moment you sign up.
From sign-up to your first live eSIM
Sandbox is yours immediately. Only live access involves a person, and only once.
- 1Sign up
Create an account with your work email and agree to the API terms. Your sandbox exists at once, with $100 of test credit. No approval, no call.
- 2Build in sandbox
Create a
numk_test_key and integrate. Sandbox orders return demo eSIMs, cost nothing, and behave exactly like live. Test credit refills itself. - 3Prove it is production-ready
Simulate a short balance, a failed order and a delayed eSIM. Connect a webhook. The go-live checklist in your console ticks itself as you do.
- 4Request live
Press one button. We agree your pricing, switch live on for your account, and invoice your first credit.
- 5Go live, top up by invoice
Create a
numk_live_key and change one string. When your balance runs low, ask for another invoice; credit is added when it is paid.
Sandbox eSIMs are not real. They look right and scan as a QR code, but they will not install on a phone and never touch a network. Every sandbox order is marked "demo": true so one can never reach a traveller by accident.
An eSIM API without the usual hassle
Most eSIM suppliers start with a sales call, a contract and a minimum order. Num starts with a working sandbox.
No contract to start
Sign up, agree to plain-English terms, and you are building a minute later. Nothing to negotiate before you have seen it work.
No minimums, no monthly fee
Pay the wholesale price of each eSIM you issue and nothing else. Sell ten a month or ten thousand.
Nothing to build around it
We return the QR image and install links, and can email the eSIM to your customer under your brand. You do not need a QR library or an email template.
One simple model
Prepaid credit in US dollars. A balance, a statement, an invoice when you want more. No usage tiers to forecast.
Built for travel agencies and OTAs, eSIM resellers, and anyone who wants to sell travel data under their own brand.
Access: keys, a console, webhooks
Machines use bearer keys. People use the business console. The two never mix.
API keys
Create and revoke keys yourself. A key is shown once and we store only its hash. numk_test_ spends test credit; numk_live_ spends live credit.
Business console
At numesim.uk/business: balance, orders, statement, keys, webhooks, your go-live checklist, and which countries and packages are switched on.
Webhooks
Signed events when an eSIM is issued, fails or is cancelled, when credit is added and when your balance runs low. Retried for about a day.
Email under your brand
Pass your traveller's email on the order and Num sends them the eSIM with your brand name, the QR code and install steps. You are emailed about every purchase too.
Safe retries
Every order carries an Idempotency-Key. Send the same request twice and you get the same order back, never a second eSIM or a second charge.
Usage: two calls to an eSIM
Price a destination, place the order, give your customer the QR. The response is the eSIM.
GET /v1/catalog | Plans for a country with your wholesale price and a suggested retail price, in USD |
POST /v1/orders | Issue an eSIM: activation code, hosted QR image, install links, ICCID |
GET /v1/orders/{id} | One order; also how you poll a delayed one |
POST /v1/orders/{id}/cancel | Stop an eSIM |
GET /v1/balance · /v1/ledger | Credit remaining, and your full statement |
curl "https://numesim.uk/v1/catalog?country=JP" \
-H "Authorization: Bearer numk_test_…"
curl -X POST https://numesim.uk/v1/orders \
-H "Authorization: Bearer numk_test_…" \
-H "Idempotency-Key: booking-48213" \
-H "Content-Type: application/json" \
-d '{"planId":"np_3f9a61c0d2e47b18aa",
"country":"JP","funding":"credit"}'
{
"id": "NAH9XIRi4HjCaQwsrfc5",
"status": "active",
"mode": "sandbox",
"demo": true,
"charged": { "amount": "1.55", "currency": "USD" },
"activationCode": "LPA:1$demo.esim.test$…",
"qrUrl": "https://numesim.uk/v1/qr/….png",
"iccid": "8900000000…"
}Billing: prepaid credit, in US dollars
No card on file and nothing charged automatically. You hold a balance with us; each eSIM draws its wholesale price from it.
| Currency | US dollars for every price, charge and balance, whatever the destination. |
| How credit is added | We send an invoice. When it is paid, our team adds that amount to your balance and it appears on your statement with the invoice number. |
| What an eSIM costs | The wholesale price shown for that plan in the catalogue when you order it, less the discount agreed for your account. |
| Fees | None. No setup fee, no monthly fee, no minimum spend. |
| If your balance is short | The order is refused and nothing is issued. Nothing is ever provided on credit you have not paid for. |
| Refunds | Credit is prepaid and non-refundable, and an issued eSIM is not refunded. |
| Cancelling | You can cancel an eSIM at any time. It stops working; cancelling does not return credit. |
| If an eSIM cannot be issued | That charge is reversed to your balance automatically. |
| Num's rights | Num may cancel or suspend an eSIM or an account at any time, as set out in the API Terms. |
Questions before you start
How do we get access?
Sign up and your sandbox account exists immediately, with $100 of test credit. There is no approval for sandbox. Live access is switched on by our team when you ask for it.
Is the sandbox real?
No. Sandbox eSIMs are demo eSIMs: the activation codes look real and scan as a QR, but they do not install on a phone and never touch a mobile network. Everything else, including prices, responses, errors and webhooks, behaves exactly as live does.
What does it cost?
There is no setup fee, no monthly fee and no minimum. You pay the wholesale price of each eSIM you issue, in US dollars, less any discount agreed for your account. The catalogue endpoint returns your exact price for every plan.
How are we billed?
Prepaid credit, by invoice, in US dollars. We send an invoice, you pay it, and our team adds that amount to your balance. Each order draws its wholesale price from the balance. Your statement shows every credit and every order.
Can we get a refund?
Credit is prepaid and non-refundable, and an issued eSIM is not refunded. You can cancel an eSIM at any time, which stops it, but cancelling does not return credit. If we cannot issue an eSIM you ordered, that charge is reversed to your balance automatically.
What happens when credit runs out?
An order that would take the balance below zero is refused and nothing is issued. A balance.low webhook warns you before that, at a threshold you choose.
How does our customer get and install the eSIM?
Either way you prefer. Pass the traveller's email address on the order and Num emails them the eSIM under your brand name, with the QR code and install steps. Or deliver it yourself: every order returns a hosted QR image, the activation code, and links that open the phone's own eSIM installer.
How do we know our integration is ready for production?
The sandbox can simulate a short balance, a failed order and a delayed eSIM, and the console keeps a go-live checklist that ticks itself as your integration exercises each case. Ask for live when it is complete.
Create your sandbox account
Tell us who you are, then choose a password on the next screen. Your sandbox is ready as soon as you do.