Building YonoSIM API in the open — Vol. 1

This is Vol. 1 of a log I’m going to keep publishing until YonoSIM API gets to its first meaningful cohort of live-mode partners. Timeline honesty: V1 shipped on 2026-08-10, the “early access” framing came off on 2026-08-12, and today (2026-08-17) is a week later. The plan I followed in that week — ship the API, lean on the 45 SEO pages the /business surface picked up over the preceding month, then go quiet and wait — is the plan that produced 0 signups. So the plan has to change, and the change starts here.

What YonoSIM API is, in one paragraph

A public eSIM provisioning API. You pay the published retail rate — the same rate a traveler pays on yonosim.com, exposed in the API — bundle it inside your product (travel app, hotel checkout, insurance flow, tour operator itinerary, IoT device), and your customer never has to leave your checkout to buy connectivity. A sk_test_* sandbox key lands in your inbox on signup. No NDA, no minimum, no sales call. It’s live at api.yonosim.com.

Between Airalo Partners (NDA + a 2-6 week sales cycle) and rolling your own against raw wholesale supply (no support, no billing, no white-label). If that in-between space is a business, YonoSIM API is trying to be the Stripe of it.

How the money moves

There’s no partnership fee, no monthly platform charge, no revenue share, no seat licensing. Partners pay per eSIM at the published retail rate — the same rate a traveler pays on yonosim.com — and can mark up to their end customer for margin. If nobody in a given month issues an eSIM through the API, we don’t bill anyone. That’s what “no minimum” actually means.

It also means the honest metric here isn’t “paying customers” in the SaaS sense — there’s no subscription to count. The honest metric is live-mode integrations: a partner with real production traffic hitting the API, real eSIMs shipping to their end users, real Stripe balance being drawn down each month. That’s the number I’m going to track in this log.

Numbers I’m not hiding

Pulled straight from git, GA4, and Postgres this morning:

• 17 commits on yonosim-api since the v0.1 mock-mode drop
• 2 Fly machines serving api.yonosim.com in iad
• Traffic on the API-side surfaces — 7 days from GA4, matched exactly to the “since V1 shipped” window (2026-08-10 → 2026-08-17):
  • /en/developers — 5 sessions, 22 pageviews
  • /en/business — 4 sessions, 22 pageviews
  • /en/business/introducing-yonosim-api — 10 pageviews
  • /en/business/blog — 11 pageviews
• 0 AI-referral sessions to any /developers or /business page in that window (ChatGPT / Perplexity / Claude / Gemini / Copilot — all zero). AI is finding our consumer blog fine; it hasn’t found the B2B surface at all.
• 0 live-mode integrations — no partner issuing production eSIMs through the API yet.

YonoSIM is bootstrapped, one-person, no external funding — the goal is a durable, profitable business, not a pitch deck. This is not a “post-launch cruising toward IPO” log. This is a “the plumbing works, the pitch is sharp, nobody’s showed up yet, here’s what we’re doing about it” log.

Why I’m publishing this

Two honest inputs. The tactical one is a marketing council I ran on the situation this week — five simulated advisors came back with the same diagnosis five different ways: the surface is fine, the distribution is missing. Godin’s version was the bluntest — the 45 SEO pages are broadcasting into a void because I haven’t earned permission from a single reader.

The philosophical one is Sahil Lavingia’s The Minimalist Entrepreneur — the book that told me a solo, bootstrapped founder chasing a durable, profitable business isn’t running a smaller version of the venture game. It’s a different game. Build for a community you’re already in. Grow through the community, not through marketing. Sell manually to your first hundred customers. Build in public. Profit from day one. That book is why YonoSIM exists as a bootstrapped one-person shop instead of a pitch deck, and this log is the “build in public” discipline made concrete.

Weekly-ish through Vol. 12 minimum. Real numbers, real conversations, real wholesale pricing math with the supplier. In my voice, not YonoSIM the platform’s. I’ll be honest about whether it’s working — and if it isn’t, we’ll change the plan out loud.

Three things I fixed this week

1. Killed the “Request early access” waitlist gate on /developers. The form had already been auto-issuing a sandbox key on submit since PR #527. Sandbox mode returns mock ICCID/LPA on every call — no credit accounting, no card. The copy just didn’t say so; it still read like a “prove you belong here” ledger. Now the CTA is “Get a sandbox key” and the button says “Email me the sandbox key.” One-hour change, but the site was fighting its own positioning until I made it.

2. Rewrote the hero to name the actual alternatives. Old subhead: “between raw-wholesale APIs and retail resellers with no partner program” — vague, forgettable. New subhead: “without an Airalo Partners NDA, a Twilio-Super-SIM contract, or wiring raw wholesale supply yourself.” Naming the competitor by name is a Sales Pitch move — your buyer already has an evaluation matrix in their head; the pitch that lands is the one that walks their matrix.

3. Started this log. Which is the fix that’s supposed to compound.

The wholesale math, since someone always asks

Every eSIM sold through YonoSIM — consumer or API — runs through a single provider-agnostic aggregator on our side ( src/upstream/client.ts), so store.ts doesn’t care which upstream fulfilled. Multi-supplier by design: no single vendor’s outage takes the API down, and adding a new upstream is one adapter, not a rewrite of the surface.

Wholesale margins in this category are thin — this isn’t a buy-for-a-dollar-sell-for-ten business. What the retail rate is priced for is you: bundle it inside your product and set your own sell price on top. Every partner sees the same published number in POST /v1/plans/search. That’s the “one rate.”

Volume rebate at ~$10k+/mo is a private per-key rebate against retail. Different partners get different rebates depending on volume mix and country distribution — email [email protected] and see yours in a day.

If a wholesale contract is what you actually want, Airalo Partners will make you sign an NDA and take 2-6 weeks to give you a number. If you’d rather start building today, our published retail + volume rebate is the deal — and you can grab a sandbox key without a call.

What I’m trying next week

Three things, prioritized:

1. /business hero rewrite — same Sales Pitch structure I just applied to /developers, so the two front doors say the same thing.
2. Find three real API prospects in warm channels — no cold outreach (still not). Sharpen by naming: three specific founders whose posts I already read on X / Indie Hackers / HN, whose products would benefit from eSIM. I’ll engage thoughtfully in threads they’re already active in, and if we hit rapport I’ll ask if they want to chat. Sahil’s “first 100” discipline adapted to warm-only. I’ll name who (with permission) and how it went in Vol. 2.
3. Vol. 2 of this log. Whether the score is 0/3, 1/3, or 3/3 by then. The score is the log.

How to reach me / what I want

• Sandbox key: yonosim.com/developers — instant, no card, no call.
• Playground: api.yonosim.com/docs — shared demo key already loaded.
• Reply to this log with what you’d want to see in Vol. 2. And — if you’re building a travel-adjacent product with eSIM on your list — the first 5 founders to reply get a founder-integration cohort deal: $50 of live-mode credits on your sandbox key today (small enough for a real first production order), plus $500 more back to your Stripe balance once your live-mode volume hits $1,000. Small upfront, meaningful when you’ve actually integrated. Reply-all works — I read every reply.

— Roc · #YouOnlyNeedOneSIM

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