Backend Engineer Intern at Juspay | Mumbai | Freshers

About Juspay

Juspay is a leading global payments technology company, powering superior conversion rates, scalable and cost-effective infrastructure, and seamless customer experiences at scale for 500+ top global enterprises and banks. Founded in 2012, Juspay processes over 350M+ of India's daily digital transactions, exceeding an annualized TPV of $1 trillion with 99.999% availability. Headquartered in Bangalore, India, Juspay's global network of 1500+ payment experts operates across San Francisco, Dublin, São Paulo, and Singapore.

Juspay offers a modular, interoperable payment suite for merchants, banks and payment networks, covering open-source payment orchestration, authentication, offer management, subscription, tokenization, fraud & risk management, global payouts, reconciliation, and analytics. For banks, Juspay delivers real-time payment infrastructure (UPI stacks) and end-to-end white-label merchant acquiring solutions and payment gateways. Our marquee partners include Google Pay, Amazon Pay, Flipkart, IRCTC, Navi, Swiggy, WhatsApp Pay, Mastercard, Visa, NPCI, and more.

Nationwide Impact & Ecosystem Building

Over the past decade, Juspay has been a core enabler of India's digital payments revolution by building infrastructure, protocols and frameworks that now serve billions of users. We work as a Technology Service Provider (TSP), connecting merchants, banks, and fintechs through secure, interoperable, and scalable payment systems.

Key Highlights:

• BHIM & UPI Infrastructure: Partnered with NPCI to develop the UPI Common Library SDK and BHIM UPI App, enabling seamless and reliable UPI transactions across India. Juspay also designed the UPI Common Pin Page, now used for every UPI transaction nationwide.
• Open Ecosystem Platforms: Built open-source frameworks like HyperSwitch (a goal towards 'Linux for Payments'), HyperSDK, and HyperCheckout, empowering developers and merchants with flexibility, transparency, and full control.
• National Digital Initiatives: Contributed to India's open network efforts through projects like OCEN / HyperCredit (digital credit infrastructure) and ONDC / Namma Yatri (open mobility platform on the Beckn protocol).

Engineering at Juspay

At Juspay, engineering is our core differentiator. We design high-assurance, real-time systems that power over 350M+ daily transactions with 99.999% availability. Our engineering organization is structured around Centers of Excellence (CoEs) that focus on the dual goals of framework innovation (the Ideal) and business enablement (the Practical).

• SDK Engineering: From Presto to HyperSDK, we build secure, native frameworks that power seamless payment experiences for partners like Google Pay & Amazon Pay.
• Backend Systems: Our in-house KvDB (write-back cache db) sustains 100× traffic spikes with zero downtime, ensuring reliable performance during India-scale surges.
• Intelligence Systems: Juspay's AI engine turns live payment data into real-time routing decisions, using control-theoretic feedback loops and multi-arm RL bandits to dynamically steer transactions toward the most reliable gateways and continuously optimize success rates. (Read more in the published research paper: “A Control-Theoretic Approach to Dynamic Payment Routing for Success Rate Optimization”)
• Infrastructure & Platform: Multi-region, active-active architectures, on-prem + cloud deployments, and internal frameworks like InfraSwitch, A/B & ART on production data ensure always-on reliability and zero-downtime evolution.

What Will Your Work Look Like?

At Juspay, you'll work on deep-tech projects that blend AI, systems engineering, and first-principles design to solve challenges at the intersection of finance, infrastructure, and intelligence.

1. JusTrust – National Fraud & Trust Intelligence System: Building India's nationwide fraud management and trust infrastructure, a federated, privacy-preserving platform for real-time fraud detection (<100 ms), trust scoring, and automated investigations using Agentic AI. You'll work on building State-of-the-Art models that power the digital trust layer of India's payments ecosystem, integrating distributed systems, deterministic and explainable ML, continuous learning, and intelligent investigation frameworks.
2. Xyne Spaces – AI-Native Workspace: Building an AI-native enterprise workspace that unifies knowledge, conversations, tickets, workflows and other signals into an intelligence context layer (Org Brain). Xyne Spaces enables humans & AI agents to collaborate seamlessly through multi-agent orchestration, dynamic knowledge graphs, and context-aware interfaces. You'll design agentic systems, reasoning pipelines, execution frameworks and build domain specific models that transform fragmented enterprise data into structured, actionable intelligence for teams to search & act within a single adaptive workspace.
3. Namma Cloud – Sovereign Infrastructure DSL: You will work on building a sovereign cloud platform powered by Namma DSL, a Rust-based language for declarative infrastructure that acts as a digital twin of the entire data center. This aims to run on-premises and within regulated bank environments, spanning the entire stack from bare metal to applications, orchestrated by OpenStack, Ceph, and Kubernetes.

Who Are We Looking For?

We're seeking forward deployed engineers, researchers, and system thinkers who aren't afraid to operate at the edge of complexity, where AI, large-scale data systems, and societal-scale infrastructure intersect. You'll be joining a team that builds foundational systems for India's digital trust, payments, and intelligence network where every line of code carries real-world impact.

We're looking for people who:

• Think from first principles: You can translate complex theory in math, systems, or AI into elegant, scalable, and reliable implementations.
• Forward Deployed Engineers (FDE): Engage actively with external stakeholders to translate complex domain requirements into scalable technical solutions with right abstraction.
• Build 0 → 1 systems: You're excited to pioneer in AI/ML, Agentic AI, or real-time distributed systems, turning abstract ideas into working frameworks.
• Understand Samaaj–Sarkaar–Bazaar: You appreciate the interplay between society, governance, & markets, and can design within the constraints of real-world institutions.