config package in the application repository is the source of truth; when in doubt, confirm keys and defaults in source.
Fields with no defaults are left blank in the examples.
In
blnk.json, most duration fields use integer seconds (lock_duration, lock_wait_timeout, hot_pair_ttl). Blnk multiplies them by time.Second on load.queue.backpressure_check_interval and typesense.backpressure_retry_interval use nanoseconds in JSON (for example 500000000 for 500ms). Environment variables for all duration fields use Go duration format (for example 500ms, 5s).# Project
# Defaults to "Blnk Server" when not set.
BLNK_PROJECT_NAME=Blnk Server
# Server
# Port defaults to 5001. SSL and secure mode are off by default.
BLNK_SERVER_SECURE=false
BLNK_SERVER_SECRET_KEY=
BLNK_SERVER_PORT=5001
BLNK_SERVER_MAX_REQUEST_BODY_SIZE_MB=5
BLNK_SERVER_MAX_UPLOAD_SIZE_MB=256
BLNK_METRICS_BEARER_TOKEN=
# Database
# DNS is required for Blnk to start successfully. Docker default shown below.
# CONNECTION_MAX_LIFETIME and CONNECTION_MAX_IDLE_TIME are integer seconds.
BLNK_DATA_SOURCE_DNS=postgres://postgres:password@postgres:5432/blnk?sslmode=disable
BLNK_DATABASE_MAX_OPEN_CONNS=50
BLNK_DATABASE_MAX_IDLE_CONNS=25
BLNK_DATABASE_CONN_MAX_LIFETIME=30m
BLNK_DATABASE_CONN_MAX_IDLE_TIME=5m
# Redis
# DNS is required for Blnk to start successfully. Docker default shown below.
BLNK_REDIS_DNS=redis:6379
BLNK_REDIS_SKIP_TLS_VERIFY=false
# Typesense
# Docker default shown for the Typesense endpoint. The API key defaults to "blnk-api-key".
BLNK_TYPESENSE_DNS=http://typesense:8108
BLNK_TYPESENSE_KEY=blnk-api-key
BLNK_TYPESENSE_BACKPRESSURE_RETRY_INTERVAL=5s
# Transactions
# LOCK_DURATION and LOCK_WAIT_TIMEOUT are integer seconds.
BLNK_TRANSACTION_BATCH_SIZE=1000
BLNK_TRANSACTION_MAX_QUEUE_SIZE=1000
BLNK_TRANSACTION_MAX_WORKERS=10
BLNK_TRANSACTION_LOCK_DURATION=1m
BLNK_TRANSACTION_LOCK_WAIT_TIMEOUT=3s
BLNK_TRANSACTION_INDEX_QUEUE_PREFIX=transactions
BLNK_TRANSACTION_ENABLE_COALESCING=true
BLNK_TRANSACTION_ENABLE_QUEUED_CHECKS=false
BLNK_TRANSACTION_DISABLE_BATCH_REFERENCE_CHECK=false
# Queue
BLNK_QUEUE_TRANSACTION=new:transaction
BLNK_QUEUE_WEBHOOK=new:webhook
BLNK_QUEUE_INDEX=new:index
BLNK_QUEUE_INFLIGHT_EXPIRY=new:inflight-expiry
BLNK_QUEUE_INFLIGHT_COMMIT=new:inflight-commit
BLNK_QUEUE_NUMBER_OF_QUEUES=20
BLNK_QUEUE_INSUFFICIENT_FUND_RETRIES=false
BLNK_QUEUE_MAX_RETRY_ATTEMPTS=5
BLNK_QUEUE_MONITORING_PORT=5004
BLNK_QUEUE_WEBHOOK_CONCURRENCY=20
# Hot-lane and worker tuning
# HOT_PAIR_TTL is integer seconds.
BLNK_QUEUE_ENABLE_HOT_LANE=false
BLNK_QUEUE_HOT_QUEUE_NAME=hot_transactions
BLNK_QUEUE_HOT_QUEUE_CONCURRENCY=1
BLNK_QUEUE_HOT_PAIR_TTL=300
BLNK_QUEUE_HOT_PAIR_LOCK_CONTENTION_THRESHOLD=3
BLNK_QUEUE_REJECT_LOCK_CONTENTION_IMMEDIATELY=false
BLNK_QUEUE_TRANSACTION_WORKER_CONCURRENCY=4
BLNK_QUEUE_ENABLE_BACKPRESSURE=true
BLNK_QUEUE_BACKPRESSURE_MEMORY_PERCENT=85
BLNK_QUEUE_BACKPRESSURE_MAX_PENDING_TASKS=0
BLNK_QUEUE_BACKPRESSURE_CHECK_INTERVAL=500ms
# Rate limiting
# These are the runtime defaults used when rate limiting is not configured. Values are integer seconds.
BLNK_RATE_LIMIT_RPS=5000000
BLNK_RATE_LIMIT_BURST=10000000
BLNK_RATE_LIMIT_CLEANUP_INTERVAL_SEC=10800
# Reconciliation
# Retry delay uses Go duration format.
BLNK_RECONCILIATION_DEFAULT_STRATEGY=one_to_one
BLNK_RECONCILIATION_PROGRESS_INTERVAL=100
BLNK_RECONCILIATION_MAX_RETRIES=3
BLNK_RECONCILIATION_RETRY_DELAY=5s
# Webhooks
# Leave these blank until you are ready to send Slack alerts or webhooks.
BLNK_SLACK_WEBHOOK_URL=
BLNK_WEBHOOK_URL=
BLNK_WEBHOOK_HEADERS={}
# Observability
BLNK_ENABLE_TELEMETRY=false
BLNK_ENABLE_OBSERVABILITY=false
# Blnk Cloud DSN for managed monitoring export. Format: https://<write-key>@<host>/<project-id>
BLNK_CLOUD_DSN=
# Self-hosted OTLP HTTP export (works when observability is enabled)
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=
OTEL_EXPORTER_OTLP_METRICS_ENDPOINT=
# Tokenization
BLNK_TOKENIZATION_SECRET=
# Backups
BLNK_BACKUP_DIR=
BLNK_AWS_ACCESS_KEY_ID=
BLNK_AWS_SECRET_ACCESS_KEY=
BLNK_S3_ENDPOINT=
BLNK_S3_BUCKET_NAME=
BLNK_S3_REGION=
{
"project_name": "Blnk Server",
"server": {
"secure": false,
"secret_key": "",
"port": "5001",
"metrics_bearer_token": "",
"max_request_body_size_mb": 5,
"max_upload_size_mb": 256
},
"data_source": {
"dns": "postgres://postgres:password@postgres:5432/blnk?sslmode=disable",
"max_open_conns": 50,
"max_idle_conns": 25,
"conn_max_lifetime": 1800,
"conn_max_idle_time": 300
},
"redis": {
"dns": "redis:6379",
"skip_tls_verify": false,
"pool_size": 100,
"min_idle_conns": 20
},
"typesense": {
"dns": "http://typesense:8108",
"backpressure_retry_interval": 5000000000
},
"type_sense_key": "blnk-api-key",
"transaction": {
"batch_size": 1000,
"max_queue_size": 1000,
"max_workers": 10,
"lock_duration": 60,
"lock_wait_timeout": 3,
"index_queue_prefix": "transactions",
"enable_coalescing": true,
"enable_queued_checks": false,
"disable_batch_reference_check": false
},
"queue": {
"transaction_queue": "new:transaction",
"webhook_queue": "new:webhook",
"index_queue": "new:index",
"inflight_expiry_queue": "new:inflight-expiry",
"inflight_commit_queue": "new:inflight-commit",
"number_of_queues": 20,
"insufficient_fund_retries": false,
"max_retry_attempts": 5,
"monitoring_port": "5004",
"webhook_concurrency": 20,
"enable_hot_lane": false,
"hot_queue_name": "hot_transactions",
"hot_queue_concurrency": 1,
"hot_pair_ttl": 300,
"hot_pair_lock_contention_threshold": 3,
"reject_lock_contention_immediately": false,
"transaction_worker_concurrency": 4,
"enable_backpressure": true,
"backpressure_memory_percent": 85,
"backpressure_max_pending_tasks": 0,
"backpressure_check_interval": 500000000
},
"rate_limit": {
"requests_per_second": 5000000,
"burst": 10000000,
"cleanup_interval_sec": 10800
},
"reconciliation": {
"default_strategy": "one_to_one",
"progress_interval": 100,
"max_retries": 3,
"retry_delay": 5
},
"notification": {
"slack": {
"webhook_url": ""
},
"webhook": {
"url": "",
"headers": {}
}
},
"enable_telemetry": false,
"enable_observability": false,
"cloud_dsn": "",
"tokenization_secret": "",
"backup_dir": "",
"aws_access_key_id": "",
"aws_secret_access_key": "",
"s3_endpoint": "",
"s3_bucket_name": "",
"s3_region": ""
}