The Weather Company Data APIs vs Xweather Weather API

The Weather Company Data APIs

A wide weather data API with 168 API references built from OpenAPI documents, global 4 km current conditions, hourly history from June 2015 and a status page with component history. Keys come only through a sales-reviewed trial or contract, travel only in the URL, and the terms that govern the API are not published.

Xweather Weather API

A public OpenAPI file with 236 operations, a hosted MCP server in the official registry and a free tier of 15,000 accesses a month suit agents. REST credentials travel only in the query string, per-minute limits are unpublished, and the group terms bar commercial use of free plans and passing data to third parties unless a service description allows it.

The Weather Company Data APIs

1. Send units, language and format=json with a location on every v3 call, plus Accept-Encoding: gzip, which the usage guide marks as required.
2. Keep the key out of logs and client-side code, because it travels in the query string as apiKey.
3. Treat a 401 as either a bad key, an endpoint outside the key's package or an exceeded limit, and treat a 204 as no data for the query.
4. Each forecast duration (3day to 15day) is a separate entitlement. Request only durations the contract covers.
5. Use /v3/aggcommon to combine up to 10 products in one request. Each product and each location still counts as one call.

Xweather Weather API

1. Check success and error.code on every response. Application errors such as invalid_location return HTTP 200 with success false
2. Send fields, limit and plimit. The docs put a 15-day hourly forecast at about 600 KB, and about 25 KB with three fields
3. Read X-Cost-Tokens after each call. Cost is the endpoint multiplier times the intervals requested, so narrow from and to
4. For MCP, send Authorization: Bearer <client_id>_<client_secret> and avoid the api_key query parameter, which puts the secret in the URL
5. Add include_tags or include_tools to the MCP URL to load only the tool groups the task needs
6. On 429 read Retry-After and the X-RateLimit-Reset-* headers. maxhits_min clears at the next minute, maxhits at the period reset