
Nicolás Meléndez developed and maintained core backend features for the exactly/exa and exactly/mobile repositories over 16 months, focusing on secure card issuance, transaction processing, and risk management. He engineered robust API integrations, including Panda and Sardine, and implemented smart contract workflows using TypeScript and Node.js. His work emphasized reliability through improved error handling, observability with Sentry, and concurrency control for transaction flows. By delivering features like PDF statement generation, cross-chain onboarding, and automated fraud controls, Nicolás addressed business needs for scalability and data accuracy. His contributions demonstrated depth in backend architecture, cryptography, and testing, resulting in resilient, maintainable systems.
February 2026 (2026-02) – exactly/mobile: Focused on reliability and test quality, delivering server-side error handling improvements and expanded card statement tests. The changes reduce unnecessary retries on replay revert errors and add robust testing utilities, enabling faster feedback and safer deployments.
February 2026 (2026-02) – exactly/mobile: Focused on reliability and test quality, delivering server-side error handling improvements and expanded card statement tests. The changes reduce unnecessary retries on replay revert errors and add robust testing utilities, enabling faster feedback and safer deployments.
January 2026 (2026-01) highlights for exactly/mobile: Delivered two high-value server-side features that improve customer experience and analytics fidelity. Card Statement Generation enables PDF statements from card activity (purchases and repayments), reducing manual work and increasing transparency. User Source Attribution Tracking adds a Client-Fid header in authentication/registration and persists the source in credentials storage, improving analytics accuracy and onboarding attribution. No major bugs reported this month; stability improvements across authentication and credential storage. Business impact: streamlined billing statements, better data governance, and more reliable attribution for marketing/product decisions. Technologies/skills demonstrated: server-side development, PDF generation, header-based attribution, credentials storage, and database/schema updates, with attention to data privacy and maintainability.
January 2026 (2026-01) highlights for exactly/mobile: Delivered two high-value server-side features that improve customer experience and analytics fidelity. Card Statement Generation enables PDF statements from card activity (purchases and repayments), reducing manual work and increasing transparency. User Source Attribution Tracking adds a Client-Fid header in authentication/registration and persists the source in credentials storage, improving analytics accuracy and onboarding attribution. No major bugs reported this month; stability improvements across authentication and credential storage. Business impact: streamlined billing statements, better data governance, and more reliable attribution for marketing/product decisions. Technologies/skills demonstrated: server-side development, PDF generation, header-based attribution, credentials storage, and database/schema updates, with attention to data privacy and maintainability.
2025-12 — exactly/mobile: Implemented three key capability areas to reduce noise, strengthen risk controls, and improve resilience in transaction processing. Key deliveries: 1) Notification suppression for market share activities to prevent unnecessary alerts and enhance user experience (commit ba6da13b7b8b1f4218162a64a69641e2d5bbf47d). 2) Risk assessment enhancements: Sardine API integration for risk management, transaction risk scoring, and background risk evaluation to improve security and reliability (commits ddc66a83caf37d9c4911b7b2673e7bc65e09f4bc; a6c130c4d596dc354c66aaef460fcf699acf6ae1; cbde413a11735fac8922eee16845af9c0d86ebd6). 3) Flexible card status handling in transaction processing: process transactions without requiring ACTIVE card state, increasing resilience (commit 566a1f0461c365581b7cd1b0fc8cbb2e7f891dca). Overall impact: reduced alert fatigue, stronger security posture through proactive risk assessment, and more robust, scalable transaction workflows. Technologies/skills: server-side development, external API integration (Sardine), background processing, risk scoring, and resilient design.
2025-12 — exactly/mobile: Implemented three key capability areas to reduce noise, strengthen risk controls, and improve resilience in transaction processing. Key deliveries: 1) Notification suppression for market share activities to prevent unnecessary alerts and enhance user experience (commit ba6da13b7b8b1f4218162a64a69641e2d5bbf47d). 2) Risk assessment enhancements: Sardine API integration for risk management, transaction risk scoring, and background risk evaluation to improve security and reliability (commits ddc66a83caf37d9c4911b7b2673e7bc65e09f4bc; a6c130c4d596dc354c66aaef460fcf699acf6ae1; cbde413a11735fac8922eee16845af9c0d86ebd6). 3) Flexible card status handling in transaction processing: process transactions without requiring ACTIVE card state, increasing resilience (commit 566a1f0461c365581b7cd1b0fc8cbb2e7f891dca). Overall impact: reduced alert fatigue, stronger security posture through proactive risk assessment, and more robust, scalable transaction workflows. Technologies/skills: server-side development, external API integration (Sardine), background processing, risk scoring, and resilient design.
November 2025 highlights for exactly/mobile: Backend features and reliability improvements delivering stronger card workflows, asset handling, and network compatibility. These changes unlock tighter product-card linkage, broader asset deployment, and expanded blockchain support, while enhancing reliability through explicit replay error handling and dependency upgrades, driving better user experience and operational resilience.
November 2025 highlights for exactly/mobile: Backend features and reliability improvements delivering stronger card workflows, asset handling, and network compatibility. These changes unlock tighter product-card linkage, broader asset deployment, and expanded blockchain support, while enhancing reliability through explicit replay error handling and dependency upgrades, driving better user experience and operational resilience.
For October 2025 (2025-10), delivered the Nonce Management System in exactly/exa to improve transaction reliability under timeouts. The changes include introduction of a nonce manager utility, updates to mock keeper and keeper utility, and stabilization of tests by fixing flaky nonce reset tests. Commits: ad7c6e6f0452a7657e7ef3d693e98b688f4b7f09 (server: reset nonce on tx receipt timeout) and 22372a9730cdef722aa58c381d447bd5b20448dd (server: fix nonce reset flaky test). Business value: reduces transaction failures due to timeouts, ensures nonce integrity across retries, enhances test stability and deployment confidence. Technical highlights: added nonce manager utility, integrated with server, mocks updated to align with new behavior.
For October 2025 (2025-10), delivered the Nonce Management System in exactly/exa to improve transaction reliability under timeouts. The changes include introduction of a nonce manager utility, updates to mock keeper and keeper utility, and stabilization of tests by fixing flaky nonce reset tests. Commits: ad7c6e6f0452a7657e7ef3d693e98b688f4b7f09 (server: reset nonce on tx receipt timeout) and 22372a9730cdef722aa58c381d447bd5b20448dd (server: fix nonce reset flaky test). Business value: reduces transaction failures due to timeouts, ensures nonce integrity across retries, enhances test stability and deployment confidence. Technical highlights: added nonce manager utility, integrated with server, mocks updated to align with new behavior.
Month: 2025-09. Repository: exactly/exa. This period delivered the Automatic Credit Mode Activation on New Cards feature, with backend logic to auto-enable credit mode when collateral exists and notify users via push notifications. No major bugs fixed this month. Overall impact: reduces manual steps for users, ensures correct credit state on new cards, and improves onboarding and engagement for users with collateral. Technologies demonstrated include backend server changes, conditional logic based on user collateral, and integration with the push notification system. Commit referenced: f703a527940591efe5511897854dc694c0bb28d2.
Month: 2025-09. Repository: exactly/exa. This period delivered the Automatic Credit Mode Activation on New Cards feature, with backend logic to auto-enable credit mode when collateral exists and notify users via push notifications. No major bugs fixed this month. Overall impact: reduces manual steps for users, ensures correct credit state on new cards, and improves onboarding and engagement for users with collateral. Technologies demonstrated include backend server changes, conditional logic based on user collateral, and integration with the push notification system. Commit referenced: f703a527940591efe5511897854dc694c0bb28d2.
Exactly/exa – August 2025: Four focused deliveries across testing reliability, fraud control, error signaling, and observability. Key outcomes include more reliable Activity API tests, automated user deactivation on failed force captures to mitigate fraud risk, explicit HTTP 557 PandaError for liquidity issues, and enhanced observability for declined transactions via richer logs and Sentry attributes. These changes improve release confidence, accelerate incident response, and strengthen client error handling. Tech stack and skills demonstrated include server-side testing, unit/integration coverage, error handling patterns, and observability tooling (Sentry).
Exactly/exa – August 2025: Four focused deliveries across testing reliability, fraud control, error signaling, and observability. Key outcomes include more reliable Activity API tests, automated user deactivation on failed force captures to mitigate fraud risk, explicit HTTP 557 PandaError for liquidity issues, and enhanced observability for declined transactions via richer logs and Sentry attributes. These changes improve release confidence, accelerate incident response, and strengthen client error handling. Tech stack and skills demonstrated include server-side testing, unit/integration coverage, error handling patterns, and observability tooling (Sentry).
In July 2025, delivered two features in the exactly/exa repository: Observability Instrumentation for IDs in Panda Hook and User Notifications for refund processing and alert text improvements. These changes improve observability, tracing, and debugging of events and transactions, and enhance user-facing alerts around refunds and purchases. There were no reported major bugs fixed this month; focus was on feature delivery and quality improvements. The work strengthens reliability, visibility into event-flow, and customer communication, supporting faster issue resolution and better user experience.
In July 2025, delivered two features in the exactly/exa repository: Observability Instrumentation for IDs in Panda Hook and User Notifications for refund processing and alert text improvements. These changes improve observability, tracing, and debugging of events and transactions, and enhance user-facing alerts around refunds and purchases. There were no reported major bugs fixed this month; focus was on feature delivery and quality improvements. The work strengthens reliability, visibility into event-flow, and customer communication, supporting faster issue resolution and better user experience.
June 2025 monthly summary focusing on key business and technical achievements across the exactly/exa repository. Core efforts prioritized data quality, reliability, and security in card and Panda activity workflows, with emphasis on deduplication, settlement reconciliation, robust event handling, and streamlined authentication/session flows. Delivered hardening of health checks, removal of deprecated providers, and improved error handling and observability to enable scalable, accurate transaction processing and data analytics.
June 2025 monthly summary focusing on key business and technical achievements across the exactly/exa repository. Core efforts prioritized data quality, reliability, and security in card and Panda activity workflows, with emphasis on deduplication, settlement reconciliation, robust event handling, and streamlined authentication/session flows. Delivered hardening of health checks, removal of deprecated providers, and improved error handling and observability to enable scalable, accurate transaction processing and data analytics.
May 2025 summary for exactly/exa. Delivered four key improvements across PIN management, activity visibility, reliability, and cross-chain onboarding. Key features and bugs: Card PIN Management and PIN API Integration enabled end-to-end PIN handling with API and encryption utilities; Activity Feed Enhancements added merchant icons and fixed legacy WETH withdraw display; Activity Hook Robustness improved error handling, deduplicate ETH/WETH notifications, and added retry for poke account operations; Cross-Chain Account Factory Address Normalization standardized account creation across chains by removing hardcoded addresses. Impact: higher data accuracy in activity feeds, more reliable notifications, secure PIN workflows, and consistent cross-chain onboarding. Technologies/skills demonstrated: API integration, encryption utilities, robust error handling, retry patterns, deduplication, and cross-chain refactoring.
May 2025 summary for exactly/exa. Delivered four key improvements across PIN management, activity visibility, reliability, and cross-chain onboarding. Key features and bugs: Card PIN Management and PIN API Integration enabled end-to-end PIN handling with API and encryption utilities; Activity Feed Enhancements added merchant icons and fixed legacy WETH withdraw display; Activity Hook Robustness improved error handling, deduplicate ETH/WETH notifications, and added retry for poke account operations; Cross-Chain Account Factory Address Normalization standardized account creation across chains by removing hardcoded addresses. Impact: higher data accuracy in activity feeds, more reliable notifications, secure PIN workflows, and consistent cross-chain onboarding. Technologies/skills demonstrated: API integration, encryption utilities, robust error handling, retry patterns, deduplication, and cross-chain refactoring.
April 2025 highlights: Delivered KYC country code header with robust fallback, enabling improved data quality for risk assessment; added multi-chain issuer checks with chain-specific checkers and Optimism-compatible registration logic; enabled Panda card issuance and management with enhanced user resolution, credential handling, and event processing; extended persona data collection with annual salary and monthly volume ranges, and improved Sentry reporting for validation issues; maintained stability by downgrading react-native-persona from 2.10.0 to 2.9.6. The work demonstrates cross-chain architecture, identity and credential flows, observability, and careful dependency management to preserve tooling compatibility.
April 2025 highlights: Delivered KYC country code header with robust fallback, enabling improved data quality for risk assessment; added multi-chain issuer checks with chain-specific checkers and Optimism-compatible registration logic; enabled Panda card issuance and management with enhanced user resolution, credential handling, and event processing; extended persona data collection with annual salary and monthly volume ranges, and improved Sentry reporting for validation issues; maintained stability by downgrading react-native-persona from 2.10.0 to 2.9.6. The work demonstrates cross-chain architecture, identity and credential flows, observability, and careful dependency management to preserve tooling compatibility.
March 2025: Delivered business-value features and reliability improvements across the exactly/exa repository. Modernized the Proposal System to support generalized workflows, improved error handling and observability, refined activity data accuracy and UI, enabled Panda refunds, and strengthened concurrency controls for authorization. These changes increase throughput, reduce support tickets, and improve security and maintainability.
March 2025: Delivered business-value features and reliability improvements across the exactly/exa repository. Modernized the Proposal System to support generalized workflows, improved error handling and observability, refined activity data accuracy and UI, enabled Panda refunds, and strengthened concurrency controls for authorization. These changes increase throughput, reduce support tickets, and improve security and maintainability.
February 2025: Delivered Panda-centric enhancements and reliability improvements across the Panda issuance workflow in the exactly/exa repository. Key features include Panda card art, migration from Cryptomate to Panda with KYC templates, and dynamic persona templates; updated card creation onboarding, limits, and notifications with improved validation and transaction updates; improved Panda debit activity parsing and data mapping; and internal reliability and test improvements. These changes reduce onboarding friction, improve financial data accuracy, enhance user notifications, and strengthen testing and reliability. Tech stack/areas involved include backend services, migration patterns, logging, and provider-based data collectors; testing practices were improved with random keeper mocks. Key achievements include: - Panda Issuance, Card Art, and Persona Templates deployed, including migration path and KYC support - Card Creation Onboarding, Limits, and Notifications enhancements with updated weekly limit and order validation - Panda Debit Activity Logging Improvements for accurate activity parsing and mapping - Internal Reliability and Testing Improvements: session parsing fixes, provider-separated collectors, simplified card name handling, and random keeper mocks for test isolation
February 2025: Delivered Panda-centric enhancements and reliability improvements across the Panda issuance workflow in the exactly/exa repository. Key features include Panda card art, migration from Cryptomate to Panda with KYC templates, and dynamic persona templates; updated card creation onboarding, limits, and notifications with improved validation and transaction updates; improved Panda debit activity parsing and data mapping; and internal reliability and test improvements. These changes reduce onboarding friction, improve financial data accuracy, enhance user notifications, and strengthen testing and reliability. Tech stack/areas involved include backend services, migration patterns, logging, and provider-based data collectors; testing practices were improved with random keeper mocks. Key achievements include: - Panda Issuance, Card Art, and Persona Templates deployed, including migration path and KYC support - Card Creation Onboarding, Limits, and Notifications enhancements with updated weekly limit and order validation - Panda Debit Activity Logging Improvements for accurate activity parsing and mapping - Internal Reliability and Testing Improvements: session parsing fixes, provider-separated collectors, simplified card name handling, and random keeper mocks for test isolation
January 2025 monthly summary for developer work focused on the exactly/exa repository. Key reliability improvement delivered for Panda Card creation tests, with a robust credential derivation approach to replace a hardcoded user ID. This reduces test flakiness, accelerates CI feedback, and supports faster iteration on Panda Card workflows.
January 2025 monthly summary for developer work focused on the exactly/exa repository. Key reliability improvement delivered for Panda Card creation tests, with a robust credential derivation approach to replace a hardcoded user ID. This reduces test flakiness, accelerates CI feedback, and supports faster iteration on Panda Card workflows.
December 2024 monthly summary for exactly/exa: Delivered Panda API integration for virtual cards and secure Panda data display; enhanced error tracking with phone context in inquiries; added transaction options to poke functionality; removed the unneeded transaction receipt timeout workaround, streamlining server flows. These changes deliver tangible business value by enabling Panda-based card issuance, improving debugging and observability, increasing transaction configurability, and simplifying the transaction flow.
December 2024 monthly summary for exactly/exa: Delivered Panda API integration for virtual cards and secure Panda data display; enhanced error tracking with phone context in inquiries; added transaction options to poke functionality; removed the unneeded transaction receipt timeout workaround, streamlining server flows. These changes deliver tangible business value by enabling Panda-based card issuance, improving debugging and observability, increasing transaction configurability, and simplifying the transaction flow.
November 2024 performance focused on reliability, observability, and external data resilience across two repositories (exactly/exa and wevm/viem). Key work included expanding test coverage for server clearing, tightening tracing and error handling, and introducing robust timeouts and retry logic for external calls. A critical race condition in waitForTransactionReceipt under concurrent polling was fixed, accompanied by tests and listener cleanup improvements.
November 2024 performance focused on reliability, observability, and external data resilience across two repositories (exactly/exa and wevm/viem). Key work included expanding test coverage for server clearing, tightening tracing and error handling, and introducing robust timeouts and retry logic for external calls. A critical race condition in waitForTransactionReceipt under concurrent polling was fixed, accompanied by tests and listener cleanup improvements.

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