Web Traffic & API Analysis Expert Needed (Burp Suite)

We are looking for an experienced web traffic analyst and API specialist with strong Burp Suite skills to investigate changes made to a web platform’s account registration process. The website uses a phone number as the first step of registration. We currently have an automated workflow that interacts with this registration process. Recently, the platform appears to have introduced changes that affect how registrations are handled, particularly in relation to specific mobile operators. We need an expert to analyze the registration flow and determine exactly what has changed. Our goal is to understand whether the registration process relies on operator-specific validations, API requests, identifiers, risk checks, or other mechanisms, and to identify the root cause of the current behavior. We are looking for a detailed technical analysis and recommendations for compliant implementation approaches based on the findings. Responsibilities: * Analyze and compare all registration-related HTTP/HTTPS requests, responses, headers, cookies, tokens, and API calls using Burp Suite. * Review the complete registration workflow from start to finish. * Identify how the platform detects, validates, or associates submitted phone numbers with specific mobile operators. * Compare registration behavior across different operators (where authorized and available) to identify differences in validation logic, API responses, risk scoring, or backend processing. * Investigate any recently introduced controls such as carrier validation, device fingerprinting, geolocation checks, anti-abuse protections, verification requirements, or third-party services involved in registration. * Analyze authentication tokens, session identifiers, and account-related credentials generated during successful registrations and determine how they interact with registration-related endpoints. * Determine the exact step, request, response, or validation that causes registrations to fail or become restricted. * Document findings with supporting evidence, including request/response samples, screenshots, and traffic captures. * Provide recommendations for compliant workflow adjustments, integrations, or alternative implementation approaches. Requirements: * Advanced experience with Burp Suite. * Strong understanding of web applications, APIs, authentication flows, sessions, cookies, and network traffic analysis. * Experience troubleshooting registration and verification workflows. * Ability to identify changes in application behavior and backend validation logic. * Strong documentation and reporting skills. Deliverables: * Detailed technical report explaining the registration workflow. * Root-cause analysis of the issue affecting registrations. * Comparison of previous versus current behavior. * Analysis of token, session, and authentication handling relevant to the registration process. * Supporting evidence, including traffic captures, request/response samples, and screenshots. * Technical recommendations and possible implementation options based on the findings. Additional Information: * Before hiring, I will provide the platform details so you can review the project and confirm whether it matches your expertise. * If necessary for testing purposes, I can provide a phone number that can be used to reproduce the registration process and assist in identifying the exact source of the issue. * The objective is to accurately determine what changed in the registration flow and identify any viable technical solutions, alternative workflows, or implementation approaches supported by the platform’s current behavior. Please include examples of similar API analysis, web traffic investigation, reverse-engineering, or registration workflow troubleshooting projects you have completed.