Declined.io Developer Documentation

Integrate payment recovery automation into your billing stack. Send events when payments fail, mark recoveries when customers pay, and receive outbound webhooks as sequences progress.

Quick start

Send your first event to the Events API. Each request must include a unique event_id — replays with the same ID return 200 with status: "duplicate" and do not create side effects.

curl

curl -X POST https://app.declined.io/api/v1/events \
  -H "Authorization: Bearer decl_sandbox_sk_..." \
  -H "Content-Type: application/json" \
  -d '{
    "event_id": "evt_001",
    "type": "payment_failed",
    "customer_id": "cus_123",
    "invoice_id": "inv_456",
    "amount": 24900,
    "currency": "usd",
    "provider": "stripe"
  }'

Official SDKs

Client libraries wrap authentication, idempotency, and typed payloads. Each language is maintained in the declined-sdk monorepo:

Node.js — npm install declined
Python — pip install declined
Ruby — gem install declined
PHP — composer require declined/sdk
Go — go get github.com/Enoros/declined-sdk/declined-go
Java — Maven: io.declined:declined

Core concepts

Authentication — Bearer secret keys, live vs sandbox environments, publishable vs secret key types
Events — Ingest billing signals that enqueue recovery sequences
Recoveries — Stop sequences when payment succeeds outside hosted recovery
Webhooks — Receive signed outbound notifications
REST API — Full endpoint reference and HTTP semantics