> ## Documentation Index > Fetch the complete documentation index at: https://docs.tangoanalytics.com/llms.txt > Use this file to discover all available pages before exploring further. # Add Readings For Custom Meter > A `POST` request will create a meter reading for the custom meter with a matching identifier. > A constraint violation error will occur if a custom meter has an existing meter reading for a given timestamp. ##### Timestamp Format The timestamp must be in the ISO 8601 standard format. The following are examples of supported formats: | Format | Example | | --- | --- | | YYYY-MM-DDTHH:mm:ss.SSSZ | 2020-01-03T09:07:21.215Z | | YYYY-MM-DDTHH:mm:ss.SSZ | 2020-01-03T09:07:21.21Z | | YYYY-MM-DDTHH:mm:ss.SZ | 2020-01-03T09:07:21.2Z | | YYYY-MM-DDTHH:mm:ss.SSS | 2020-01-03T09:07:21.215 | | YYYY-MM-DDTHH:mm:ss.SS | 2020-01-03T09:07:21.21 | | YYYY-MM-DDTHH:mm:ssZ | 2020-01-03T09:07:21Z | | YYYY-MM-DDTHH:mm:ss | 2020-01-03T09:07:21 | | YYYY-MM-DDTHH:mmZ | 2020-01-03T09:07Z | | YYYY-MM-DDTHH:mm | 2020-01-03T09:07 | ##### Meter Reading Value Format The maximum allowed scale for a meter reading value is limited to 16 digits, with the precision limited to 4 digits. Any meter reading values that exceed the precision of 4 digits will be rounded and result in a loss of precision. The input also accepts scientific notation formats such as "2.5E+8". These values are constrained by the limitations above. ## OpenAPI ````yaml /tango_watchwire/integrations/guides/watchwire-api.yaml post /custommeters/{customMeterId}/meterreadings openapi: 3.1.0 info: title: WatchWire API version: 1.0.0 description: >- The WatchWire Platform has APIs that allow you to access your data programmatically. There are several APIs designed for the modules in the WatchWire platform including - Invoice Data, Real-Time, Accounts Payable, and Measurement & Verification. All are highly scalable, and secure APIs that communicate over HTTPS RESTful protocols with JSON based documents. > **Note**: Not all WatchWire modules are available as an API. # Authentication You need credentials to access the APIs - it is the same credentials as your WatchWire login. The `/authenticate` will return a Token that needs to be included in the header of every subsequent request. The token renews with each request and expires after 60 minutes of inactivity (at which point you will need to re-authenticate and get a new token). > Please contact the WatchWire team for any questions or request for API credential access. # Error Codes There will be various error codes specific to the API you are using, but generally follows these principles: * `Unauthorized` - *you are unauthenticated or unauthorized to request actions on an asset* * `Asset doesn't exist` - *the item you are querying for doesn't exist* * `Server error`\- *general exception raised in our application code* # Rate limit Rate limited to 10 transactions per meter / second servers: - url: https://auth.replace-me.example.com description: Authentication service (Postman variable {{ww-api-baseurl}}) - url: https://realtime.replace-me.example.com description: RealTime API (Postman variable {{gateway-realtime-api}}) - url: https://ap.replace-me.example.com description: Accounts Payable API (Postman variable {{gateway-ap-api}}) - url: https://invoice.replace-me.example.com description: Invoice API (Postman variable {{portal-api-baseurl}}) - url: https://mv.replace-me.example.com description: Measurement & Verification API (Postman variable {{invoice-api}}) security: - BearerAuth: [] tags: - name: Authentication - name: RealTime API - Custom Meter - name: RealTime API - Meter Readings - name: RealTime API - Meter Readings Aggregations - name: RealTime API - Meter Readings Batch Operations - name: RealTime API - Obvius Meter Readings - name: Accounts Payable API - Audit Statements - name: Accounts Payable API - Nexus Statements - name: Accounts Payable API - Standard Statements - name: Accounts Payable API - Statement PDFs - name: Invoice API - Reference IDs - name: Invoice API - Invoice - name: Measurement & Verification API - M&V paths: /custommeters/{customMeterId}/meterreadings: post: tags: - RealTime API - Meter Readings summary: Add Readings For Custom Meter description: >- A `POST` request will create a meter reading for the custom meter with a matching identifier. > A constraint violation error will occur if a custom meter has an existing meter reading for a given timestamp. ##### Timestamp Format The timestamp must be in the ISO 8601 standard format. The following are examples of supported formats: | Format | Example | | --- | --- | | YYYY-MM-DDTHH:mm:ss.SSSZ | 2020-01-03T09:07:21.215Z | | YYYY-MM-DDTHH:mm:ss.SSZ | 2020-01-03T09:07:21.21Z | | YYYY-MM-DDTHH:mm:ss.SZ | 2020-01-03T09:07:21.2Z | | YYYY-MM-DDTHH:mm:ss.SSS | 2020-01-03T09:07:21.215 | | YYYY-MM-DDTHH:mm:ss.SS | 2020-01-03T09:07:21.21 | | YYYY-MM-DDTHH:mm:ssZ | 2020-01-03T09:07:21Z | | YYYY-MM-DDTHH:mm:ss | 2020-01-03T09:07:21 | | YYYY-MM-DDTHH:mmZ | 2020-01-03T09:07Z | | YYYY-MM-DDTHH:mm | 2020-01-03T09:07 | ##### Meter Reading Value Format The maximum allowed scale for a meter reading value is limited to 16 digits, with the precision limited to 4 digits. Any meter reading values that exceed the precision of 4 digits will be rounded and result in a loss of precision. The input also accepts scientific notation formats such as "2.5E+8". These values are constrained by the limitations above. operationId: addReadingsForCustomMeter parameters: - name: customMeterId in: path required: true schema: type: integer description: Unique identifier of the custom meter. requestBody: required: true content: application/json: schema: type: object properties: timestamp: type: string value: type: integer example: timestamp: 2020-01-02T19:00:00.000+0000 value: 5 responses: '200': description: Successful response '401': description: Unauthorized - missing, invalid or expired token security: - BearerAuth: [] servers: - url: https://realtime.replace-me.example.com description: RealTime API (Postman variable {{gateway-realtime-api}}) components: securitySchemes: BearerAuth: type: http scheme: bearer description: >- Token returned by `POST /authenticate`. Expires after 60 minutes of inactivity. ````