> ## Documentation Index > Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt > Use this file to discover all available pages before exploring further. # List the registered rails, their declared properties and their state > The rail contract, made visible. Reading this before attempting a bypass is how a client discovers that a rail declares hasBypass: false rather than discovering it from a 422. Listing requires an identified operator holding channels:read, because the listing returns declaredBy, an operator identity. ## OpenAPI ````yaml /es/openapi/v3-current/jd-courier.yaml get /v1/channels openapi: 3.1.0 info: description: >- The JD Courier API. Operators use it to manage the engines, the ownership map, the delivery modes and bypass of each rail, the retained messages, the SPB send journal and reconciliation. Engines use it to resolve the owner of a key, claim their Pix Automático recurrences and declare their Pix Automático payment legs. title: JD Courier API version: v1.0.0 servers: [] security: - BearerAuth: [] tags: - description: >- The engine registry: the cores that consume the JD channel through the Courier, each with its participant set name: Engines - description: 'The ownership map: which engine owns each key. Every change is audited.' name: ownership - description: >- The rails: what each declares about itself, its state per tenant, and the bypass declaration name: channels - description: >- The engines' side of the ownership map: resolution for the on-us gate, authoritative and never advisory, the claim of a Pix Automático recurrence the engine holds, and the declaration of a payment leg it holds. name: ownership-query - description: >- The durable message store: redelivery on demand, without asking the vendor again name: ledger - description: >- Count reconciliation per rail: E(m) = C(m) + T(m) + R(m), the sequence gaps it saw, and the sends whose return leg never arrived name: assurance - description: >- The SPB send journal: every send, written before it leaves, and the sends whose outcome is unknown. A by-hand close records an operator's finding and never resends. name: send-journal - description: >- Per-(tenant, channel) state an operator acts on: lifting a durable channel halt name: channel-leases - description: >- Messages the Courier holds because no engine could receive them. A routing or delivery retention leaves by itself once its cause lifts, or when an operator asks for its routing decision to be run again. name: retained paths: /v1/channels: get: tags: - channels summary: List the registered rails, their declared properties and their state description: >- The rail contract, made visible. Reading this before attempting a bypass is how a client discovers that a rail declares hasBypass: false rather than discovering it from a 422. Listing requires an identified operator holding channels:read, because the listing returns declaredBy, an operator identity. operationId: listChannels responses: '200': content: application/json: schema: $ref: '#/components/schemas/ChannelList' description: OK '401': content: application/problem+json: schema: $ref: '#/components/schemas/Detail' description: Unauthorized '403': content: application/problem+json: schema: $ref: '#/components/schemas/Detail' description: Forbidden '500': content: application/problem+json: schema: $ref: '#/components/schemas/Detail' description: Internal Server Error '503': content: application/problem+json: schema: $ref: '#/components/schemas/Detail' description: Service Unavailable components: schemas: ChannelList: additionalProperties: false properties: items: items: $ref: '#/components/schemas/ChannelListItem' type: array required: - items type: object Detail: additionalProperties: true properties: code: description: >- Stable, machine-readable domain error code scoped to the emitting service (format: -NNNN). type: string detail: description: >- A human-readable explanation specific to this occurrence of the problem. examples: - Property foo is required but is missing. type: string errors: description: Optional list of individual error details items: $ref: '#/components/schemas/ErrorDetail' type: - array - 'null' instance: description: >- A URI reference that identifies the specific occurrence of the problem. examples: - https://example.com/error-log/abc123 format: uri type: string status: description: HTTP status code examples: - 400 format: int64 type: integer title: description: >- A short, human-readable summary of the problem type. This value should not change between occurrences of the error. examples: - Bad Request type: string type: default: about:blank description: A URI reference to human-readable documentation for the error. examples: - https://example.com/errors/example format: uri type: string upstream: $ref: '#/components/schemas/Upstream' description: >- RFC 9457 extension member: the error a proxied third-party provider reported. Absent unless the emitting service explicitly surfaced one. type: object ChannelListItem: additionalProperties: false properties: descriptor: $ref: '#/components/schemas/ChannelDescriptor' state: $ref: '#/components/schemas/ChannelState' required: - descriptor - state type: object ErrorDetail: additionalProperties: false properties: location: description: >- Where the error occurred, e.g. 'body.items[3].tags' or 'path.thing-id' type: string message: description: Error message text type: string value: description: The value at the given location type: object Upstream: additionalProperties: false properties: code: description: The upstream provider's own error code, verbatim. examples: - E4001 type: string message: description: >- The upstream provider's own error message, verbatim (bounded, never its raw response body). examples: - account not found at provider type: string type: object ChannelDescriptor: additionalProperties: false properties: channelId: enum: - spb - pix type: string consumerTopology: enum: - SINGLE_WRITER - STATELESS type: string deliveryModes: items: enum: - SINGLE_ENGINE - ALL_ENGINES - REFUSE type: string type: array durabilityRule: enum: - PERSIST_BEFORE_DECIDE - PERSIST_BEFORE_ACK type: string financialFamilies: items: maxLength: 64 type: string type: array hasBypass: type: boolean ingressModel: enum: - DRAIN_PULL - TERMINATED_PUSH type: string moneyBearingFamilies: items: maxLength: 64 type: string type: array ownershipKinds: items: type: string type: array retentionReasons: items: type: string type: array required: - channelId - ingressModel - consumerTopology - durabilityRule - hasBypass - financialFamilies - deliveryModes - ownershipKinds - retentionReasons type: object ChannelState: additionalProperties: false properties: bypass: description: Null when no engine is in bypass on this rail. oneOf: - $ref: '#/components/schemas/ChannelBypass' - type: 'null' channelId: enum: - spb - pix type: string lastReconciliationAt: format: date-time type: - string - 'null' lease: description: >- Null on a rail with no single-writer consumer, or before its drain first ran. oneOf: - $ref: '#/components/schemas/ConsumerLease' - type: 'null' reconciliationRunning: type: boolean required: - channelId type: object ChannelBypass: additionalProperties: false properties: active: type: boolean channelId: enum: - spb - pix type: string declaredAt: format: date-time type: - string - 'null' declaredBy: maxLength: 128 type: - string - 'null' engineId: pattern: ^[a-z0-9-]{1,32}$ type: - string - 'null' reason: maxLength: 512 type: - string - 'null' suspendedGuarantees: description: Guarantees explicitly suspended while the bypass is active. items: maxLength: 64 type: string type: array required: - channelId - active type: object ConsumerLease: additionalProperties: false properties: epoch: format: int64 minimum: 0 type: integer haltReason: maxLength: 64 type: - string - 'null' heartbeatAt: description: The holder's last heartbeat. format: date-time type: string held: description: >- A holder is recorded and its heartbeat is inside the lease TTL (SPB_LEASE_TTL_SEC, database clock). False on a stale heartbeat: a lease another holder may take over. type: boolean holderId: maxLength: 128 type: - string - 'null' lastProgressAt: description: The drain's last completed read of the vendor queue, empty or not. format: date-time type: - string - 'null' progressAgeSeconds: format: int64 minimum: 0 type: integer state: enum: - consuming - idle - halted_ambiguous - awaiting_retry type: string required: - held - epoch - heartbeatAt - state type: object securitySchemes: BearerAuth: bearerFormat: JWT description: JWT bearer token issued by the identity provider. scheme: bearer type: http ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.