Senior Base24 Developer

Job Title : Senior Base24 / Base24 Classic Developer

Location : Brazil

Client : Fiserv

Budget : $4,500 USD as CONTRACTOR (No benefits)

Duration : Long-term

Employment Type : Full-Time

About the Role

We are seeking an experienced Base24 / Base24 Classic Developer to support payment switch development, enhancement, and operational stability within a high-volume card transaction environment. The ideal candidate has hands-on experience working with Tandem / HP NonStop systems , Base24 modules, issuer / acquirer interfaces, and ATM / POS transaction processing flows.

This role requires strong technical depth in transaction 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 support Base24 / Base24 Classic applications on HP NonStop (Tandem) platform .

Maintain and modify ATM / 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 of incident / problem resolution .

Implement code enhancements, patches, and release changes in alignment with governance and compliance standards.

Design and execute system integration testing, regression testing, and certification testing with 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 detailed technical documentation, release notes, and operational runbooks .

Required Skills & Experience

5+ years hands-on experience with Base24 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 supporting high-availability, transaction-intensive payment switching platforms.

Hands-on experience in debugging, log analysis, and performance tuning in a production environment.

Knowledge of Visa / Mastercard authorization and clearing , card bin tables, key exchange, PIN translation.

Experience in incident management, change control, and release management .

Good to Have

Exposure to Base24-eps migration or development.

Experience working with Fiserv, First Data, TSYS, ACI Postilion, or Opus environments.

Knowledge of EMV, HSM (Thales / SafeNet) , cryptographic key management.

Experience with Jira, Confluence, Git , and CI / CD toolchains.

Education

Bachelor’s degree in Computer Science, Engineering, Information Systems, or related field (or equivalent work experience).