Sogolytics

Sogolytics is survey software with response analytics, logic branching, custom branding, API access, and a respondent panel. The Free Pro plan costs nothing, is free forever, and requires no credit card. It allows 15 projects per year, up to 100 responses per project, 200 responses per year, and 200 email invitations per year. Pro costs $99 a month and includes 1,250 responses per month, 15,000 responses per year, and 2,000 email invitations per month. Pro Max costs $199 a month, with 3,000 responses per month, 40,000 per year, and 4,000 email invitations per month. Surveys can contain up to 40 questions, and a 15-day trial is listed. Sogolytics, founded in 2013 and headquartered in Herndon, Virginia, lists API as its platform.

It suits people creating surveys who need branching, branding, analytics, respondent access, or an API. The free tier fits limited annual projects, while higher response allowances are available on paid plans.