The Technical Co-Founder Podcast with Fexingo: Engineering Founders, CTOs, and Building from Code

In this episode, Lucas and Luna explore how a fast-growing B2B SaaS company called DataSync avoided a catastrophic production outage by catching a silent schema drift before it reached production. They walk through the specific tooling — a combination of declarative migrations, CI checks, and a custom drift detector that compares the intended schema against the live database on every deploy. The c...

Episode 78 dives into a specific technical decision: how one early-stage infrastructure startup replaced its sidecar proxies with WebAssembly modules running in the data plane. Lucas and Luna walk through the company's original architecture—a standard Envoy sidecar per pod—and the problems that emerged as they scaled to 200 microservices: memory overhead, version drift, and cold-start latency. The...

In this episode of The Technical Co-Founder Podcast, Lucas and Luna dive into eBPF (extended Berkeley Packet Filter), a technology that lets developers run sandboxed programs in the Linux kernel without changing kernel code or loading modules. They explore how a startup called Pixie (acquired by New Relic) built a no-instrumentation observability platform using eBPF, enabling engineers to trace ev...

Episode 76 of The Technical Co-Founder Podcast digs into how a mid-stage B2B SaaS company called SyncLayer used GraphQL Federation to unify 20 independent microservices into a single data graph — without rewriting any backend. Lucas walks through the specific problem: frontend teams were making 8 to 12 round trips per page load, and the API gateway had become a bottleneck with spaghetti logic. Lun...

Lucas and Luna break down how a fast-growing B2B SaaS startup swapped internal-only feature flags for user-facing toggles—and cut rollout friction by 60 percent. They walk through the architecture: a thin audit layer in the API gateway, a Redis-backed toggle store with per-tenant overrides, and a React hook that exposes beta features to power users without touching production code. The guest engin...

Episode 74 of The Technical Co-Founder Podcast dives into how a 12-person B2B SaaS startup called DataLoop replaced screenshots with live embedded analytics and cut their enterprise sales cycle from 9 months to under 4. Lucas and Luna unpack the architectural decisions behind embedding a full analytics layer using Supabase, Cube.js, and React. They discuss the trade-off between building vs buying,...

Most startups don't need a perfect architecture on day one — they need to ship. In this episode, Lucas and Luna dig into the pragmatic art of glue code: the scripts, hacks, and duct-tape integrations that let early-stage teams build features before they have the infrastructure to do it cleanly. They walk through a real-world example from a SaaS company that used a 200-line Python script to bridge...

Episode 72 of The Technical Co-Founder Podcast. Lucas and Luna dive into how a mid-stage B2B SaaS startup called DataRail used database sharding to handle explosive growth from 2 million to over 10 million users without breaking the bank. They break down the architecture: why DataRail chose hash-based sharding over range-based, how they migrated live with zero downtime using a dual-write strategy,...

Episode 71 dives into how a fintech startup called Nucleus uses Terraform and Pulumi to manage infrastructure across AWS, GCP, and Azure from a single codebase. Lucas and Luna explore the trade-offs between declarative and imperative IaC, how Nucleus cut provisioning time from days to minutes, and the hidden costs of multi-cloud complexity. They also touch on the operational discipline required to...

Episode 70 dives into a real-world implementation of OpenTelemetry at a fintech startup handling 50 million API calls daily. Lucas and Luna break down how the company replaced three proprietary monitoring tools with a single open-source observability framework, cutting mean time to detection by 60 percent and saving $2 million annually in licensing costs. They walk through the specific technical d...

Episode 69 of The Technical Co-Founder Podcast: Lucas and Luna explore how a fast-growing payments startup, Transactly, adopted trunk-based development to ship code ten times per day. They break down the three-pillar strategy behind it: short-lived feature branches merged within hours, a mandatory pass through a staging environment via ephemeral preview deployments, and a culture of small reversib...

Lucas and Luna dive into LaunchDarkly's feature flag architecture and how it lets developers ship incomplete code to production without breaking the user experience. They break down the difference between flags for release vs. experimentation, discuss the concept of toggling technical debt, and share a real-world example of how one engineering team used progressive delivery to roll out a breaking...

In this episode of The Technical Co-Founder Podcast, Lucas and Luna dive into a specific CI optimization technique that transformed a real startup's engineering velocity. They discuss how BuildKit cache mounts can dramatically speed up Docker image builds by persisting package manager caches across builds, eliminating redundant downloads. The conversation centers on a case study of a 20-person Saa...

Lucas and Luna dig into contract testing — a practice that lets teams verify service-to-service compatibility without spinning up full integration environments. They walk through a real-world case: a fintech startup that cut its pre-deployment failure rate by 70 percent after adopting consumer-driven contract tests with Pact. Lucas explains how contracts act as executable documentation, keeping AP...

In this episode of The Technical Co-Founder Podcast, Lucas and Luna explore how a growing SaaS startup replaced brittle mock-based tests with test containers — spinning up real PostgreSQL, Redis, and S3-compatible storage in ephemeral Docker containers for integration tests. The result: test flakiness dropped by 80 percent, false positives nearly vanished, and the CI pipeline sped up by 40 percent...

Episode 64 of The Technical Co-Founder Podcast with Fexingo dives into continuous profiling — a technique that captures production CPU, memory, and I/O usage at the function level in real time. Lucas and Luna examine how a fintech startup called ClearPay used continuous profiling to identify a single hot loop in their transaction engine that was wasting millions of CPU cycles per second. By fixing...

On this episode of The Technical Co-Founder Podcast, Lucas and Luna explore how a fintech startup called LedgerSync uses blameless postmortems to turn outages into engineering culture wins. They walk through a specific incident where an API timeout cascade took down payment processing for 40 minutes—and how the postmortem process led to a 90 percent reduction in similar incidents over six months....

In this episode of The Technical Co-Founder Podcast, Lucas and Luna dive into how a fast-growing fintech startup called FloatPay uses automated regression testing to ship code multiple times a day without breaking things. They walk through FloatPay's specific approach: a pipeline that runs a full regression suite in under three minutes using parallelized containers and a clever diff-based test sel...

In this episode of The Technical Co-Founder Podcast, Lucas and Luna dive into a concrete case: how a mid-stage fintech startup uses distributed tracing to cut mean time to resolution from hours to minutes. They walk through the implementation of OpenTelemetry spans, how the team convinced skeptical engineers to instrument their code, and the surprising discovery that 40% of their production bugs w...

Episode 60 of The Technical Co-Founder Podcast digs into a single case: how a mid-stage SaaS startup called LogiFlow built an internal developer platform (IDP) to reduce cognitive load on its engineering team. Lucas and Luna walk through why IDPs are gaining traction as an alternative to complex microservice architectures, and how LogiFlow's platform cut onboarding time from two weeks to two days...

In this episode of The Technical Co-Founder Podcast, Lucas and Luna dive into how a B2B SaaS startup replaced three customer support tiers with a single semantic search layer. The case: a company called SupportAI (fictional) built a vector-search system that routes, resolves, and escalates queries automatically using embeddings. Lucas walks through the architecture: precomputed embeddings for FAQ...

In episode 58 of The Technical Co-Founder Podcast, Lucas and Luna explore how a startup called Opsless uses platform engineering to let product teams deploy infrastructure without a dedicated ops team. They walk through Opsless's core approach: building an internal developer platform (IDP) that abstracts Kubernetes, CI/CD, and monitoring into self-service APIs. Lucas breaks down how Opsless reduce...

Lucas and Luna explore how a fintech startup called PayShield uses chaos engineering to deliberately break its own infrastructure in production. They walk through a specific case: how PayShield simulated a regional AWS outage to test its failover logic, discovering a silent deadlock in its payment-processing queue. The episode covers the team's weekly 'break things' schedule, the tooling they buil...

Episode 56 of The Technical Co-Founder Podcast explores how a fintech startup called LedgerLayer used observability—not just monitoring—to slash its incident response time from over an hour to under twelve minutes. Lucas and Luna walk through the specific tools and cultural shifts that made the difference: structured logging, distributed tracing with OpenTelemetry, and a practice called 'error bud...

In episode 55 of The Technical Co-Founder Podcast, Lucas and Luna explore how early-stage startups are deploying knowledge graphs to connect siloed internal data without a data warehouse overhaul. They break down the concrete case of a 12-person fintech startup that built a lightweight knowledge graph on top of its existing PostgreSQL database using open-source tools like Neo4j and custom embeddin...