Contact person: Business Client

Phone:Show

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Location: Kokkedal, Denmark

Budget: Recommended by industry experts

Time to start: As soon as possible

Project description:
"I need a working OAuth 1.0a flow wired into my existing web application so it can talk to the Mastercard APIs behind their secure gateway. The site is already up and running; I’ll share the tech stack and credentials after we start.

Scope for this first phase is intentionally lean:
• Add the OAuth 1.0a signing logic (consumer key, secret, RSA-SHA1 signature, nonce, timestamp, base string).
• Handle request token, user redirect/authorization, and access-token exchange.
• Demonstrate a single successful call to one protected Mastercard endpoint (I’ll specify which once NDA is signed).
• Supply concise setup notes so I can reproduce the flow locally.

Please keep external libraries to a minimum, comment the code clearly, and flag any prerequisites. Prior experience with Mastercard Sandbox, payment gateways, or similar OAuth 1.0a–secured APIs is a plus." (client-provided description)