docs — subly.

overview

What is Subly?

Subly lets a business charge customers on a recurring schedule using stablecoins on Solana — like a card subscription, but on-chain and self-custodial. A merchant creates a plan, shares a checkout link, and Subly collects each billing period automatically. Customers subscribe with one wallet signature and can cancel any time from their own wallet.

Non-custodial

Funds stay in the customer’s wallet. Subly only pulls what the customer approved, each period.

On-chain

Plans, subscriptions, and payments live on Solana — transparent and verifiable.

Audited

The underlying subscriptions program is audited by Cantina.

for merchants

Start selling subscriptions

Everything happens from the dashboard at app.subly.fi.

Connect & sign in

Open app.subly.fi, connect your Solana wallet (Phantom, Solflare, or any wallet), then open Settings → Sign in with wallet. Signing is a free message signature (not a transaction) — it lets the dashboard track your plans, subscribers, and revenue.

Create a plan

Set the token (USDC), the price, and the billing period (e.g. every 1 hour, day, week, or month). Keep “Let Subly collect payments automatically” on so Subly pulls each period for you. Creating a plan is a single on-chain transaction.

Share your checkout

Each plan has a Share button with a hosted checkout link (subly.fi/checkout?plan=…) and an embed snippet. Put it on your site, in your bio, or send it directly.

Get paid automatically

When a customer subscribes, Subly collects the agreed amount each billing period and deposits it to your wallet’s token account. You can watch subscribers and revenue on the dashboard. No invoicing, no manual follow-up.

Settings & integrations

From Settings you can copy your API key, set a webhook URL to receive subscription events (created, payment received/failed, cancelled), and add an email for payment alerts.

for customers

Subscribing & staying in control

Subscribe in one signature

Open the merchant’s checkout link, connect your wallet, and press Subscribe. You’ll need some USDC for the payments and a little SOL for network fees. Subscribing approves a delegation with the plan’s terms — the amount and the period are fixed on-chain.

Your money stays yours

Subly is non-custodial. Your funds never leave your wallet to sit with Subly. Each billing period, only the agreed amount is pulled — never more. You can see every payment on-chain.

Cancel anytime, from your wallet

Connect your wallet at app.subly.fi → Subscriptions → Unsubscribe. Cancelling is your transaction alone — a merchant cannot cancel for you, and cannot charge you after you cancel. Your subscription stays active until the end of the period you already paid for, then stops.

plan lifecycle

Winding a plan down (merchants)

A plan has two independent controls. Knowing the difference avoids confusion:

End date

When the plan expires. Must be at least one billing period in the future, so current subscribers keep the period they’ve paid for. A plan can only be deleted after its end date has passed (which reclaims the on-chain rent).

Sunset

Stops new subscriptions immediately. Existing subscribers are unaffected. Sunsetting is terminal — a plan can’t go back to active.

Typical wind-down: Active → set an end date (and optionally Sunset to stop new sign-ups) → after the end date passes, Delete to close the plan and recover rent.

security & trust

Why it’s safe

Self-custody. Subly never holds customer funds. Money stays in the customer’s wallet and is only pulled per the on-chain delegation they approved.
Fixed terms. The price and billing period are locked on-chain when you subscribe. A merchant cannot charge more than agreed, or charge you after you cancel.
Audited program. The subscriptions program Subly builds on is audited by Cantina.
Open source. The code is public on GitHub — anyone can review it.

Review the code at github.com/Subly-Fi.

faq

Frequently asked

Does Subly hold my money?

No. Subly is non-custodial. Funds stay in your wallet and are only pulled, per period, up to the amount you approved when subscribing.

Which tokens are supported?

USDC today, with support for SPL tokens. The token is set by the merchant on each plan.

Can a merchant charge me more than agreed?

No. The amount and billing period are fixed on-chain when you subscribe. A merchant cannot increase them for an existing subscription, and cannot charge you after you cancel.

How do I cancel?

Connect your wallet at app.subly.fi → Subscriptions → Unsubscribe. It’s your transaction. The subscription stays active until the end of the period you already paid for, then stops.

Can a merchant cancel my subscription?

No — only you can cancel, because it requires your signature. A merchant can stop offering a plan (sunset), but cannot end your subscription for you.

What if my balance is too low when a payment is due?

That period’s payment is skipped. After repeated failed attempts the subscription may lapse. Keep enough USDC in your wallet to cover the next payment.

What’s the shortest billing period?

One hour. Periods can be set in hours, days, weeks, or months.

Ready to start?

Create your first plan or subscribe in minutes.

launch app back to home

How Subly works