Backend service

Rafiki’s backend service is the software’s main service for handling business logic and external communication. The service is responsible for:

• Exposing the endpoints of the Open Payments APIs for public clients to initiate payments and look up information. This is the external communication piece.
• Exposing an Interledger connector to send and receive STREAM packets with peers.
• Enabling you to manage accounts and track liquidity.
• Exposing an internal GraphQL Backend Admin API for service operators to manage accounts, liquidity, and application settings, like peering relationships.

Requirements

The following are required when using the backend service.

• A Redis database as a cache to share STREAM connection details and total amounts received across processes
• A Postgres database, separate from the auth service’s database, for Open Payments resources
• TigerBeetle or a separate Postgres database for accounting liquidity

  Note

  You can use the same database instance of Postgres for the backend service, auth service, and accounting liquidities (if not using TigerBeetle). However, separate database schemas are required within the Rafiki instance to maintain boundaries between the objects being managed.

You must also set the environment variables for the backend service.

Open Payments

The backend service exposes the Open Payments APIs, which are auth-protected using an opinionated version of the Grant Negotiation and Authorization Protocol (GNAP). Review the auth service page for more details about grant authorization and authentication.

The backend service allows you to manage Open Payments incoming payments, quotes, and outgoing payments. Quotes and outgoing payments call the ILP connector, described in the next section, to send ILP packets. Quoting sends unfulfillable probe packets, for example to determine a transaction’s cost before executing the payment. Outgoing payments send packets as part of executing the payment.

Interledger connector

The backend service exposes an ILP connector to send and receive ILP packets between peers.

Some of the responsibilities of a connector include:

• Authenticating packets against ILP account credentials.
• Forwarding packets to a sender or receiver.
• Rejecting a packet for any number of reasons, including expiration, insufficient liquidity, rate limit exceeded, or if the amount exceeds the maxPacketAmount agreed to by the connector and its peer.
• Converting currencies.
• Fulfilling packets with an internal STREAM server.

The backend service includes an HTTP server listening on the configured CONNECTOR_PORT. Your connector can receive incoming packets via HTTP and/or direct calls from within the backend service. An incoming packet is only accepted if it’s from a configured peer and accompanied by your peer’s incoming HTTP authToken.

Similarly, if a packet’s destination address corresponds to a peer, your connector will forward the packet to your peer over HTTP, along with your peer’s outgoing HTTP authToken.

Auth tokens

You and your peer should have exchanged incoming and outgoing auth tokens as part of establishing your peering relationship.

A packet can either continue on to your peer via HTTP or terminate at your Rafiki instance’s STREAM server. If the packet terminates at your STREAM server, your connector will attempt to extract and decode the payment tag from the packet’s destination address. When your connector successfully matches the tag with a locally managed wallet address or incoming payment, the connector will not forward the packet. Instead, it will credit the corresponding balance and track the total amount received in Redis to support STREAM receipts. Packets addressed to a wallet address happen via SPSP.

GraphQL Backend Admin API

The backend service exposes a GraphQL Backend Admin API to manage assets, peers, wallet addresses, Open Payments resources, and several types of liquidity.

Environment variables

Required

Variable	Helm value name	Default	Description
AUTH_SERVER_GRANT_URL	backend.serviceUrls.AUTH_SERVER_GRANT_URL	undefined	The endpoint on your Open Payments authorization server to grant a request.
AUTH_SERVER_INTROSPECTION_URL	backend.serviceUrls.AUTH_SERVER_INTROSPECTION_URL	undefined	The endpoint on your Open Payments authorization server to introspect an access token.
DATABASE_URL	backend.postgresql.host, backend.postgresql.port, backend.postgresql.username, backend.postgresql.database, backend.postgresql.password	postgresql://postgres:password@localhost:5432/development	The Postgres database URL of the database storing your resource data. For Helm, these components are provided individually.
EXCHANGE_RATES_URL	backend.serviceUrls.EXCHANGE_RATES_URL	undefined	The endpoint your Rafiki instance uses to request exchange rates.
ILP_ADDRESS	backend.ilp.address	undefined	The ILP address of your Rafiki instance.
ILP_CONNECTOR_URL	backend.ilp.connectorUrl	undefined	The ILP connector address where ILP packets are received.
KEY_ID	backend.key.id	undefined	Your Rafiki instance’s client key ID.
OPEN_PAYMENTS_URL	backend.serviceUrls.OPEN_PAYMENTS_URL	undefined	The public endpoint of your Open Payments resource server.
REDIS_URL	backend.redis.host, backend.redis.port	redis://127.0.0.1:6379	The Redis URL of the database handling ILP packet data. For Helm, these components are provided individually.
USE_TIGERBEETLE	backend.use.tigerbeetle	true	When true, a TigerBeetle database is used for accounting. When false, a Postgres database is used.
WEBHOOK_URL	backend.serviceUrls.WEBHOOK_URL	undefined	Your endpoint that consumes webhook events.

Conditionally required

Variable	Helm value name	Default	Description
INSTANCE_NAME	backend.instance.name	undefined	Your Rafiki instance’s name used to communicate for auto-peering and/or telemetry. Required when auto-peering and/or telemetry is enabled

Optional

Variable	Helm value name	Default	Description
ADMIN_PORT	backend.port.admin	3001	The port of your Backend Auth API server.
ADMIN_API_SIGNATURE_TTL_SECONDS	undefined	30	The TTL, in seconds, for which a request’s signature will be valid.
API_SECRET	undefined	undefined	N/A
API_SIGNATURE_VERSION	undefined	1	The version of the request signing algorithm used to generate signatures.
AUTO_PEERING_SERVER_PORT	backend.autoPeering.serverPort	3005	If auto-peering is enabled, the server will use this port.
CONNECTOR_PORT	backend.port.connector	3002	The port of the ILP connector for sending packets via ILP over HTTP.
ENABLE_AUTO_PEERING	backend.enable.autoPeering	false	When true, auto-peering is enabled.
ENABLE_MANUAL_MIGRATIONS	backend.enableManualMigrations	false	When true, you must run the database manually with the command npm run knex – migrate:latest –env production
ENABLE_SPSP_PAYMENT_POINTERS	backend.enable.spspPaymentPointers	true	When true, the SPSP route is enabled.
ENABLE_TELEMETRY	undefined	false	Enables the telemetry service on Rafiki.
ENABLE_TELEMETRY_TRACES	undefined	false	N/A
EXCHANGE_RATES_LIFETIME	backend.lifetime.exchangeRate	15_000	The time, in milliseconds, the exchange rates you provide via the EXCHANGE_RATES_URL are valid.
GRAPHQL_IDEMPOTENCY_KEY_LOCK_MS	backend.idempotency.keyLockMs	2000	The TTL, in milliseconds, for idempotencyKey concurrency lock on GraphQL mutations on the Backend Admin API.
GRAPHQL_IDEMPOTENCY_KEY_TTL_MS	backend.idempotency.keyTTL	86400000 (24 hours)	The TTL, in milliseconds, for idempotencyKey on GraphQL mutations on the Backend Admin API.
INCOMING_PAYMENT_CREATED_POLL_FREQUENCY_MS	undefined	1000	N/A
INCOMING_PAYMENT_CREATED_POLL_TIMEOUT_MS	undefined	10000	N/A
INCOMING_PAYMENT_EXPIRY_MAX_MS	backend.incomingPayment.expiryMaxMs	2592000000 (30 days)	The maximum into the future, in milliseconds, incoming payments expiry can be set to on creation.
INCOMING_PAYMENT_WORKER_IDLE	backend.workerIdle	200	The time, in milliseconds, that INCOMING_PAYMENT_WORKERS will wait until checking an empty incoming payment request queue again.
INCOMING_PAYMENT_WORKERS	backend.workers.incomingPayment	1	The number of workers processing incoming payment requests.
LOG_LEVEL	backend.logLevel	info	Pino log level
MAX_OUTGOING_PAYMENT_RETRY_ATTEMPTS	undefined	5	Specifies how many times an outgoing payment is retried before failing completely
NODE_ENVIRONMENT	backend.nodeEnv	development	The type of node environment: development, test, or production.
OPEN_PAYMENTS_PORT	backend.port.openPayments	3003	The port of your Open Payments resource server.
OPEN_TELEMETRY_COLLECTOR_URLS	undefined	*undefined	N/A
OPEN_TELEMETRY_EXPORT_INTERVAL	undefined	15000	N/A
OPEN_TELEMETRY_TRACE_COLLECTOR_URLS	undefined	undefined	N/A
OUTGOING_PAYMENT_WORKER_IDLE	backend.workerIdle	200	The time, in milliseconds, that OUTGOING_PAYMENT_WORKERS wait until they check an empty outgoing payment request queue again.
OUTGOING_PAYMENT_WORKERS	backend.workers.outgoingPayment	4	The number of workers processing outgoing payment requests.
POLL_INCOMING_PAYMENT_CREATED_WEBHOOK	undefined	false	N/A
PRIVATE_KEY_FILE	backend.key.file	undefined	The path to your Rafiki instance’s client private key.
QUOTE_LIFESPAN	backend.lifetime.quote	5 * 60_000 (5 minutes)	The time, in milliseconds, an Open Payments quote is valid for.
REDIS_TLS_CA_FILE_PATH	backend.redis.tlsCaFile	''	Redis TLS config
REDIS_TLS_CERT_FILE_PATH	backend.redis.tlsCertFile	''	Redis TLS config
REDIS_TLS_KEY_FILE_PATH	backend.redis.tlsKeyFile	''	Redis TLS config
SIGNATURE_SECRET	backend.quoteSignatureSecret	undefined	The secret to generate request header signatures for webhook event requests.
SIGNATURE_VERSION	backend.signatureVersion	1	The version number to generate request header signatures for webhook events.
SLIPPAGE	backend.ilp.slippage	0.01 (1%)	The accepted ILP rate fluctuation.
STREAM_SECRET	backend.ilp.streamSecret	undefined	The seed secret to generate shared STREAM secrets.
TELEMETRY_EXCHANGE_RATES_LIFETIME	undefined	86_400_000	N/A
TELEMETRY_EXCHANGE_RATES_URL	undefined	https://telemetry-exchange-rates.s3.amazonaws.com/exchange-rates-usd.json	The endpoint Rafiki will query for exchange rates. Used as a fallback if/when exchange rates aren’t provided.
TIGERBEETLE_CLUSTER_ID	undefined	0	The TigerBeetle cluster ID picked by the system that starts the TigerBeetle cluster to create a TigerBeetle client.
TIGERBEETLE_REPLICA_ADDRESSES	undefined	3004	TigerBeetle replica addresses for all replicas in the cluster. The addresses are comma-separated IP addresses/ports, to create a TigerBeetle client.
TIGERBEETLE_REPLICA_ADDRESSES.SPLIT	undefined	3004	N/A
TIGERBEETLE_TWO_PHASE_TIMEOUT_SECONDS	undefined	5	N/A
TRUST_PROXY	backend.trustProxy	false	When true, the X-Forwarded-Proto header is used to determine if connections are secure.
WALLET_ADDRESS_DEACTIVATION_PAYMENT_GRACE_PERIOD_MS	backend.walletAddress.deactivationPaymentGratePeriodMs	86400000 (24 hours)	The time into the future, in milliseconds, to set expiration of Open Payments incoming payments when deactivating a wallet address.
WALLET_ADDRESS_LOOKUP_TIMEOUT_MS	backend.walletAddress.lookupTimeoutMs	1500	The time, in milliseconds, you have to create a missing wallet address before timeout.
WALLET_ADDRESS_POLLING_FREQUENCY_MS	backend.walletAddress.pollingFrequencyMs	100	The frequency of polling while waiting for you to create a missing wallet address.
WALLET_ADDRESS_URL	backend.serviceUrls.WALLET_ADDRESS_URL	http://127.0.0.1:3001/.well-known/pay	Your Rafiki instance’s internal wallet address.
WALLET_ADDRESS_WORKER_IDLE	backend.workerIdle	200	The time, in milliseconds, that WALLET_ADDRESS_WORKERS wait until checking the empty wallet address request queue again.
WALLET_ADDRESS_WORKERS	`backend.workers.walletAddress	1	The number of workers processing wallet address requests.
WEBHOOK_MAX_RETRY	backend.webhookMaxRetry	10	The maximum number of times your Rafiki instance’s backend retries sending a certain webhook event to your configured WEBHOOK_URL.
WEBHOOK_TIMEOUT	backend.lifetime.webhook	2000 (2 seconds)	The time, in milliseconds, that your Rafiki instance will wait for a 200 response from your webhook endpoint. If a 200 response is not received, Rafiki will time out and try to send the webhook event again.
WEBHOOK_WORKER_IDLE	backend.workerIdle	200	The time, in milliseconds, that WEBHOOK_WORKERS will wait until they check the empty webhook event queue again.
WEBHOOK_WORKERS	backend.workers.webhook	1	The number of workers processing webhook events.
WITHDRAWAL_THROTTLE_DELAY	backend.withdrawalThrottleDelay	undefined	The delay in liquidity withdrawal processing.