Salla Addon Purchase

Salla Addon Billing Cycle

An addon is a purchasable extra that Salla bills on top of the app's plan. This skill owns its billing lifecycle — define → activate → renew → cancel/expire → gate. The merchant buys it inside the embedded app (purchase UX → salla-addon-purchase-embedded); Salla then drives every state change through webhooks. Activation is webhook-driven: unlock features only when app.subscription.started arrives, signature-verified.

Tools & MCPs

Use the Salla Partners MCP: define the addon in the publication's pricing section (app_publish action=set section=pricing, addons[]), then set a webhook_url via salla_apps action=connect. The app.subscription.* events below are app events — the app is subscribed to them by default, so they auto-deliver to that webhook_url. There is no subscribe call (salla_events action=subscribe is for store events only).

Salla owns billing — you never charge. Hand-offs: purchase UX (iframe) → salla-addon-purchase-embedded · pricing/entitlement primitives & gating → salla-app-billing · webhook signature/idempotency → salla-webhooks · OAuth scopes & merchant token storage for any API call you make off these events → salla-app-auth.

Step 1 — Define the Addon

Addons live in the addons[] array of the publish payload — there is no separate pricing endpoint. Each addon has an item_slug you match on for every lifecycle event. Full payload shape → salla-app-billing Step 1.

Gate: "Addon in the publish payload, published, and you know its item_slug?"

Step 2 — Set the Webhook URL (addon events auto-deliver)

The addon lifecycle rides on app.subscription.* app events — the app is subscribed to them by default, so set a webhook_url (salla_apps action=connect) and they auto-deliver. There is no subscribe call; your job is to HANDLE the events below. Confirm exact payload shapes via the App Events doc (https://docs.salla.dev/421413m0.md) before coding.

Gate: "webhook_url set (addon app.subscription.* events auto-deliver to it — no subscribe call), and a handler is wired for each event above?"

Step 3 — Activate on app.subscription.started (source of truth)

This webhook is the activation trigger. Field names below (item_type, item_slug, subscription_id, end_date, features) are illustrative — confirm the exact payload shape via salla_events action=list or the App Events doc before relying on them:

// Runs only AFTER the request is signature-verified and de-duplicated — see salla-webhooks.
if (
  payload.event === "app.subscription.started" &&
  payload.data.item_type === "addon"
) {
  const { item_slug, subscription_id, end_date, features } = payload.data;
  await entitlements.activateAddon(payload.merchant, {
    addonSlug: item_slug,
    subscriptionId: subscription_id,
    endDate: end_date,
    features: features ?? [],
  });
}

• Match the addon by item_slug (plans carry item_slug: null; addons carry the slug).
• Verify the signature, respond 200 fast, dedup → salla-webhooks. Any merchant-token API call you make from here → salla-app-auth.

Gate: "Activation fires on started + item_type === "addon", matched by item_slug, signature-verified and idempotent?"

Step 4 — Renewal, Cancellation, Expiry

Keep the stored entitlement in step with Salla — each event is the source of truth:

• renewed → extend end_date (recurring addons; track recurring vs one-time).
• canceled → mark canceled, keep access until end_date.
• expired → revoke the entitlement and re-gate the addon's features.

external_recurring addons (support_renew: true) renew on YOUR call, not automatically: POST /apps/subscriptions/{subscription_id}/renew (offline_access; handle not_renewable / auto_renew_disabled / payment_failed 403, rate_limit_exceeded 429). Salla-managed recurring addons renew on their own and you only receive renewed. Full OpenAPI schema + error contract (source of truth): https://docs.salla.dev/37396517e0.md · endpoint detail → salla-app-billing.

Persistence patterns, recurring vs one-time, and stacking the addon on the plan → salla-app-billing.

Gate: "Each lifecycle event updates the stored entitlement; expiry revokes access?"

Step 5 — Gate Features by Addon Entitlement

Gate addon-only features on the persisted entitlement (the source of truth). Gating pattern → salla-app-billing. Reflect activation back in the embedded UI → salla-addon-purchase-embedded.

Gate: "Addon features are gated on the stored entitlement, re-checked after each event?"

Lifecycle at a Glance

define addon (publish addons[])  →  merchant buys in the embedded app
        (salla-addon-purchase-embedded)
                                   │  Salla bills + confirms payment
                                   ▼  (source of truth — webhooks)
app.subscription.started (addon)  → activate entitlement
        │
        ├─ app.subscription.renewed  → extend end_date
        ├─ app.subscription.canceled → keep until end_date
        └─ app.subscription.expired  → revoke + re-gate

Key Resources