What the Data for This Category Looks Like
Steam coal market and yield rate data is primarily sourced from the Qinhuangdao Port Coal Trading Market, China Coal Transportation and Marketing Association, and Dalian Commodity Exchange. Spot price data updates daily after market close, while futures prices update in real time during trading hours. Data is provided in structured JSON format, including fields such as product code, origin, port name, daily settlement price, daily transaction average price, and total inventory. All price fields use yuan per ton as their unit, and no percentage-based statistical indicators are included.
Constraints Imposed on HTTP Interfaces and External Systems by These Characteristics
Steam coal data includes two types of sources: daily updated spot data and real-time futures data, and supports multi-dimensional filtering. This requires HTTP interfaces to support two calling modes: for real-time market data, configure short timeouts and parameters adapted for high-frequency calls; for daily report data, support scheduled batch pulling.
Multi-dimensional fields require that interface input parameters include filtering conditions such as origin and port, to avoid returning full redundant data and reduce the parsing pressure on external systems. The unified yuan per ton unit must be clearly marked in the interface response header or field comments, to prevent data errors caused by unit misunderstandings in external systems.
The multi-source data feature requires the interface to include built-in data verification logic, to ensure consistency of returned data and avoid single-source anomalies affecting the daily report broadcasting process of external systems.
Configuration Settings
| Configuration Item | Recommended Setting | Rationale |
|---|---|---|
external_api_timeout | 10-30 seconds | Steam coal real-time market data has high latency requirements. An overly long timeout will cause call blocking. Daily report data can be relaxed appropriately but should not exceed 30 seconds |
api_request_frequency | Real-time interface: 1 call per 10 seconds; daily report interface: 1 call per 86400 seconds | Real-time market update frequency matches trading hours. The daily report interface only needs to update once per day to cover full data |
response_field_whitelist | ["product code","port name","settlement price","transaction average price"] | Filter redundant non-core fields such as origin and inventory to adapt to the receiving requirements of external systems |
unit_annotation_switch | Enabled | The unit for steam coal prices is yuan per ton. Clear marking can avoid unit conversion errors in external systems |
multi_source_check_switch | Enabled | Steam coal data comes from multiple channels. Verification can filter abnormal data and improve the reliability of external system calls |
webhook_retry_times | 3 times | HTTP interfaces may have occasional fluctuations. Retrying can reduce call failure rates and avoid interrupting the daily report broadcasting process |
The parameter values provided on this page are common starting points for configuration. Actual values are affected by material form, data volume and business rules. Specific issues require specific analysis. It is recommended to test on your own samples before finalizing the configuration.
Three Common Mistakes
- Phenomenon: When calling an external interface, escape characters are unexpectedly added to price fields in the returned JSON data, causing parsing failures in the external system. Cause: The original JSON data returned by the interface was not properly escaped, and was directly spliced into the request body, resulting in format exceptions.
- Phenomenon: When configuring a real-time market interface, a 429 status code is returned, and the request is rate-limited. Cause: The call frequency was not set reasonably based on the update frequency of steam coal real-time market data, and the number of calls exceeded the interface quota.
- Phenomenon: An
aiPointsNotEnougherror is returned when calling the daily report interface. Cause: Insufficient call quota was not configured, or the number of interface calls exceeded the preset threshold.
How to Confirm Proper Configuration
- Initiate a single real-time market interface call, check whether the returned fields include the preset whitelist fields, and the unit marking is correct.
- Configure a scheduled task to call the daily report interface, verify that the update time of the returned data each day matches the official release schedule of steam coal data.
- Simulate an interface call failure scenario, check whether the preset retry mechanism is triggered, and the number of retries matches the configured value.
- View the interface data received by the external system, confirm that there are no extra escape characters or format exceptions.
Question material comes from public community discussions. Configuration values are common starting points and should be measured against your own samples. Verified on 2026-09-14.