API
Definition
Application Programming Interface — an interface that allows two software programs to communicate with each other. Modern APIs are generally REST or GraphQL, secured by authentication (API key, OAuth).
Detailed explanation
An API is an exchange contract between software programs. It defines the available endpoints (URLs), the methods (GET/POST/PUT/DELETE in REST), the accepted parameters, and the response format (JSON most of the time). Examples of APIs a freelancer regularly integrates: Stripe/Mollie (payments), HubSpot (CRM), Mailchimp (emailing), OpenAI/Anthropic (AI), Google Calendar (appointments). Designing your own public API opens up your product's ecosystem: Flowayz exposes a public API that lets integrators push specs, list projects, or synchronise contracts with Zapier or Make.
Related terms
Put these concepts into practice
Flowayz automates specification, quote and invoice creation for freelancers.
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