> ## Documentation Index > Fetch the complete documentation index at: https://docs.auth.energy/llms.txt > Use this file to discover all available pages before exploring further. # List suppliers > Returns all TI Energy Suppliers with their API endpoint URLs and active status. Use this to discover where to send tariff requests for a given supplier MPID. Publicly accessible — no authentication required. ## OpenAPI ````yaml /tariff-interop/api/openapi-tariff.yaml get /v1/suppliers openapi: 3.1.0 info: title: Tariff Interoperability API version: 0.1.1.AE description: > The Tariff Interoperability (TI) API lets Energy Smart Appliances, optimisers, and third-party services access standardised electricity tariff pricing data directly from GB energy suppliers. It is defined under the Retail Energy Code (REC) and mandated by the Smart Secure Electricity Systems (SSES) Programme. ## Two tiers of access | Tier | Who can use it | Auth required | |------|---------------|---------------| | **Public Tariff Pricing Data** | Any TI User | None | | **Consumer Specific Tariff Information** | Registered TI Users (RTI Users) with active consumer consent | OAuth 2.0 | contact: name: Auth Energy email: contact@auth.energy license: name: | © 2025 Retail Energy Code Company Ltd v0.1.0. All modifications and improves published © 2026 Auth Energy Ltd url: https://auth.energy/ servers: - url: https://register.tariff.interop description: > Central TI Register hosted by RECCo. Serves the `/v1/suppliers` and `/v1/users` endpoints only. The `v1` path prefix identifies the API version. - url: https://example-supplier.co.uk description: > Placeholder for a TI Energy Supplier's own hosted API. Each supplier runs their own instance at a URL they register with RECCo — discover it from `GET /suppliers`. Serves all `/v1/tariff`, `/v1/consent`, `/v1/webhook`, `/v1/report`, and outbound webhook endpoints. security: [] tags: - name: Registry description: >- Discover active suppliers and registered third-party users. Served by the central RECCo register. No authentication required for public data. - name: Tariffs description: >- Retrieve tariff listings and full pricing detail from a specific supplier. No authentication required. - name: Consumer Tariffs description: >- Retrieve tariff data tied to a specific consumer metering point. Requires OAuth 2.0 and active consumer consent. - name: Consent description: >- Register and revoke consumer consent linking a metering point to an RTI User via the OAuth 2.0 Authorisation Code flow. - name: Webhooks description: >- Manage webhook endpoints and receive push notifications when tariff data or consent state changes. - name: Reporting description: >- Submit periodic performance assurance metrics to RECCo (supplier obligation). paths: /v1/suppliers: get: tags: - Registry summary: List suppliers description: > Returns all TI Energy Suppliers with their API endpoint URLs and active status. Use this to discover where to send tariff requests for a given supplier MPID. Publicly accessible — no authentication required. operationId: listSuppliers parameters: - $ref: '#/components/parameters/limitParam' - $ref: '#/components/parameters/offsetParam' - name: active in: query required: false description: When `true`, returns only currently active suppliers. schema: type: boolean example: true responses: '200': description: A list of supplier register entries. content: application/json: schema: type: object required: - data - meta properties: data: type: array items: $ref: '#/components/schemas/SupplierRegisterEntry' meta: $ref: '#/components/schemas/PaginationMeta' example: data: - supplier_mpid: SEBD url: https://tariff-api.example-supplier.co.uk/SEBD display_name: Cucumber Energy status: active last_modified: '2026-11-01T10:00:00.000Z' support: tariff-support@example-supplier.co.uk meta: total: 47 limit: 20 offset: 0 next_offset: 20 '500': $ref: '#/components/responses/InternalServerError' security: [] servers: - url: https://register.tariff.interop description: Central TI Register (RECCo) components: parameters: limitParam: name: limit in: query required: false description: Maximum number of records to return. Defaults to 20, maximum 100. schema: type: integer minimum: 1 maximum: 100 default: 20 example: 20 offsetParam: name: offset in: query required: false description: Number of records to skip for pagination. Defaults to 0. schema: type: integer minimum: 0 default: 0 example: 0 schemas: SupplierRegisterEntry: type: object description: A supplier's entry in the TI Supplier Register. required: - supplier_mpid - url - display_name - last_modified - support - status properties: supplier_mpid: $ref: '#/components/schemas/SupplierMpid' support: $ref: '#/components/schemas/SupportContact' url: type: string format: uri maxLength: 200 description: >- Base URL for this supplier's tariff API. Requests take the form `{url}/{mpid}`. display_name: type: string maxLength: 100 description: Short trading name displayed to consumers and third parties. example: Cucumber Energy status: $ref: '#/components/schemas/UserStatus' last_modified: $ref: '#/components/schemas/Timestamp' PaginationMeta: type: object description: Pagination metadata included in list responses. required: - total - limit - offset properties: total: type: integer description: Total number of records matching the query. example: 47 limit: type: integer description: Maximum number of records returned in this response. example: 20 offset: type: integer description: Number of records skipped before this page. example: 0 next_offset: type: integer description: Offset to use to fetch the next page. Absent when on the last page. example: 20 SupplierMpid: type: string minLength: 4 maxLength: 4 description: Four-character Market Participant Identifier for a supplier. example: SEBD SupportContact: type: string description: >- Support contact information for Users - email, url, telephone is acceptable. example: tariff-support@acme.co.uk UserStatus: type: string description: The status of the user. enum: - active - suspended - disabled - removed example: active Timestamp: type: string format: date-time description: ISO 8601 datetime with millisecond precision. example: '2026-11-01T10:00:00.000Z' ErrorResponse: type: object required: - code - message properties: code: type: string description: Machine-readable error code. example: tariff_not_found message: type: string description: Human-readable error description. example: No tariff found for the given tariff_id and supplier MPID. details: type: string description: Additional context to help diagnose the issue. example: >- tariff_id a1b2c3d4-e5f6-7890-abcd-ef1234567890 does not exist for supplier SEBD. responses: InternalServerError: description: 500 — Unexpected server error. Retry within the 72-hour buffer window. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' ````