Google Weather API (Maps Platform) vs Stormglass API

Google Weather API (Maps Platform)

Covered by the Maps Platform SLA, 99.9 per cent with service credits. History is 24 hours only, and bulk data isn't available.

Stormglass API

A read-only weather and marine API with about 70 hourly parameters, per-source values from named national models, tide data and ERA5 history from 2014. No OpenAPI file, status page, SDK or security page was found, the free plan allows 10 requests a day, and the docs and FAQ disagree on the status code for a spent quota.

Google Weather API (Maps Platform)

1. Ask for only the days or hours you need, one location a call. Every call is one billable event
2. Page with pageSize and pageToken rather than asking for 240 hours at once
3. Check the coverage page before promising alerts. Coverage is by country
4. Refetch rather than cache. The Maps terms give no caching window for weather content
5. Restrict the key to the Weather API and your server IPs in the Cloud console

Stormglass API

1. Send the key as Authorization: KEY with no Bearer prefix. A missing or wrong key returns 403 with {"errors":{"key":"API key is invalid"}}
2. Always pass source=sg or a short source list on /weather/point. The default is every source, which multiplies the size of each hourly record
3. Treat 402 as a spent daily quota, not a billing failure, and stop until the next day. Read meta.requestCount against meta.dailyQuota on each response
4. Use /historical/point for past dates, at most 10 days a call and nothing newer than about 7 days. /weather/point looks back 14 days only
5. Send and read all times in UTC. Tide sea levels are relative to the chosen datum (MSL by default) and are not water depth