There's no need for a third party "open API" for SEC filings. The SEC already has one.[1] You can also download all SEC filings via FTP.
We've been indexing all SEC filings since 2000, from before the SEC had a public search engine. You can access them at "www.downside.com". While the site hasn't been updated in years, the indexing engine continues to run every day at 4AM, downloading the new SEC filing index for the day. Costs me $15 a month to keep it running.
There's a paid commercial service, "edgar-online.com", which also does this. They've been unnecessary since the SEC put up a search engine.
We've been indexing all SEC filings since 2000, from before the SEC had a public search engine. You can access them at "www.downside.com". While the site hasn't been updated in years, the indexing engine continues to run every day at 4AM, downloading the new SEC filing index for the day. Costs me $15 a month to keep it running.
There's a paid commercial service, "edgar-online.com", which also does this. They've been unnecessary since the SEC put up a search engine.
[1] http://www.sec.gov/edgar/searchedgar/webusers.htm