Job Title:Senior Base24 / Base24 Classic DeveloperLocation:Brazil
Client:Fiserv
Budget:$4,500 USD as CONTRACTOR (No benefits)
Duration:Long-term
Employment Type:Full-TimeAbout the Role
We are seeking an experiencedBase24 / Base24 Classic Developerto support payment switch development, enhancement, and operational stability within a high-volume card transaction environment. The ideal candidate has hands-on experience working withTandem/HP NonStop systems, Base24 modules, issuer/acquirer interfaces, and ATM/POS transaction processing flows.
This role requires strong technical depth intransaction message processing (ISO 8583),ATM/POS terminal driving, and tuning systems for high availability and performance. The developer will work closely with cross-functional teams including Product, Application Support, Network Security, and Environment Infrastructure.
Key Responsibilities
Develop, configure, enhance, and supportBase24 / Base24 Classicapplications onHP NonStop (Tandem) platform.
Maintain and modifyATM/POS transaction switch modules, authorization, settlement, and device handler components.
Monitor and troubleshoot end-to-end transaction flows including issuer/acquirer interfaces.
Analyze and resolve production issues with strong ownership ofincident/problem resolution.
Implement code enhancements, patches, and release changes in alignment with governance and compliance standards.
Design and executesystem integration testing, regression testing, and certification testingwith network partners (Visa/Mastercard).
Work with cross-functional teams to support performance tuning, batch processing, and environment stability.
Ensure secure, compliant, and resilient handling of financial transaction data.
Prepare and maintain detailedtechnical documentation, release notes, and operational runbooks.
Required Skills & Experience
5+ yearshands-on experience withBase24 or Base24 Classic.
Strong technical expertise in:
HP NonStop / Tandem (Guardian, OSS)
Pathway, TAL, COBOL, SCOBOL, C, TACL, DDL, SQL/Enscribe
ATM and POS network protocols
ISO 8583 message formats
Experience supportinghigh-availability, transaction-intensivepayment switching platforms.
Hands-on experience in debugging, log analysis, and performance tuning in a production environment.
Knowledge ofVisa/Mastercard authorization and clearing, card bin tables, key exchange, PIN translation.
Experience inincident management, change control, and release management.
Good to Have
Exposure toBase24-epsmigration or development.
Experience working withFiserv, First Data, TSYS, ACI Postilion, or Opusenvironments.
Knowledge ofEMV, HSM (Thales / SafeNet), cryptographic key management.
Experience withJira, Confluence, Git, and CI/CD toolchains.
Education
Bachelor’s degree in Computer Science, Engineering, Information Systems, or related field (or equivalent work experience).