James Cleveland

senior full stack engineer

e-mail: jc@blit.cc
github: @radiosilence
location: London or remote. Happy in an office too; I like working with people in person, as long as there's some flexibility.

Polyglot engineer. Twenty-five years of writing code, twenty of them paid for, across commercial frontend, backend, devops, mobile and embedded. Elixir and Go services, GraphQL gateways, React and Next.js, native Swift and Kotlin modules, Rust tooling, Terraform, Pulumi and Kubernetes. The language matters less than people think. What matters is a good standard library, libraries written by someone who cared, and nothing standing between me and the thing that needs to exist.

I like greenfield, and I like taking a thing that works and making it the thing it should have been, especially hard problems I can own from one end to the other. I started out freelancing, where there's nobody to hand the product to and every bug is yours, and that never left me. So I like being part of deciding what a thing should be, as well as building it.

A lot of engineering is communication - sometimes you have to lead by example, but if you can't explain the insight you have to those that are supposed to be on board, then you have to ask yourself how well you understand it yourself. A good engineer can relate concepts to people in ways that they can understand whilst still being open to the amazing ideas they might have themselves.

I love IaC because whilst you can build imperatively, being able to recreate and iterate and use development processes to declare and collaborate the infrastructure everything is built on is incredibly powerful.

LLMs and agentic code are interesting tools - they've enabled anyone to create anything easily. However, without the experience of building things, it's very easy to make mistakes, because people don't know the right questions to ask. I've had a lot of fun building MCP servers and gateways, rebuilding things in various languages, and testing their ever-increasing limits. My position is that they make it easy to not care, and to stop learning, if you let them. In the hands of someone who is open to them and has a wealth of human experience to draw upon, though, they can be an exceptional force multiplier, delivering results of high quality at great speed. Using them is a skill like any other.

What drives me is waking up every day and building something interesting. I take a lot of pride in my work, and I'm often the person people come to when something needs doing properly.

Selected Work

• Designed and led a new Elixir service to replace the reviews domain in Fresha's monolith. Moved 90M rows with the marketplace live and took reads from a 5% canary to 100% in two days. It now handles 157M requests a week.
• A WebSocket server running on a phone, written in Java and Swift as React Native modules, because the TV app it controlled ran inside a browser and couldn't host one itself.
• nano-web, an in-memory static file server in Rust with 240+ stars. It serves this page, from a cupboard.
• Got Microsoft to change Azure Policy. It couldn't express a compliance check Credit Suisse's CSPM needed, so I went to their office and made the case, and they changed the platform for my client and everyone else on it.
• Found the hole in pip. In 2013 it fetched packages over plain HTTP and verified nothing. I argued it had to check SSL certificates, and that shipped in pip 1.3 as the fix for CVE-2013-1629, with me credited by name in the release notes.
• An Android app and the entire AWS backend behind it, built from nothing for bike delivery drivers in React Native, CDK, Lambda, DynamoDB and API Gateway.

Recent Work

Senior Full Stack Engineer, Fresha 2025–Present

Key Skills: Elixir, Phoenix, Ecto, OTP, gRPC, Protobuf, GraphQL, TypeScript, Next.js, React, Zod, PostgreSQL, pgbouncer, Kafka, Snowflake, Datadog, Metabase, LiteLLM, GitHub Actions, Docker, Kubernetes

• Designed and led the service that took reviews out of the monolith. A venue's rating decides where it ranks, so this is some of the most important data in the company.
  • Built in Elixir with its own Postgres and connection pooler, gRPC contracts for other services, GraphQL for the apps, and the frontend on top.
  • Owned delivery across web, iOS, Android and backend, then owned it in production. We took reads from a 5% canary to 100% in two days (me on the pager), and it now serves around 157M requests a week.
• Moved around 90M rows with the marketplace live. There's no downtime window on a marketplace, so we moved reads, then writes, over a sync that kept the old system authoritative, with parity monitored and every stage reversible.
  • Wrote a migration tool for it, because a script wouldn't survive that much live data. It resumes with per-partition ETAs, throttles on the database's own vital signs, has a circuit breaker, shrugs off a single bad row, and has a diff mode that prints only where the two sides disagree. Fed from S3, Snowflake and a live Kafka mirror.
  • Ten teams relied on those tables, and agreeing the new boundary with all of them was as much of the job as the code.
• Kept the two systems in step through the migration, tracing every source of drift back through callers, background jobs and support tooling, cleaning up the affected data, and giving the support team new tools built on the new service.
• Made review attribution more accurate. The new service attributes reviews from the calendar booking, credits everyone who worked on the appointment, and keeps people who've moved on. That sharpened attribution for about 120,000 reviews (one in 230), so ratings reflect who did the work.
• Wired the service into Kafka and Snowflake. Changes go out through an outbox, and during the migration the service mirrored the monolith's writes in live from its topics, behind a kill switch with dead-letter queues. Rating changes feed marketplace ranking, and the tables stream into Snowflake via logical replication and CDC, poisoned rows excluded so one bad record can't stall it.
• Designed the schema and APIs around how they're read. A denormalised line-item table so aggregates, facets and sorts never join across the domain, with covering, partial and GIN full-text indexes. Cut the gRPC API to seven calls, with batch reads in one windowed query. Gave GraphQL cost ceilings, field-level redaction, role-based auth, and nullable roots so one failing field degrades a page without blanking it.
• Built AI review replies end to end: entitlement, generation in the business's own voice, moderation, publishing, and the partner UI. Everything is a draft until published, and billing reads the live balance, so running out cancels scheduled replies. 2,343 published and 129 businesses on full automation in the first weeks.
• Rebuilt consumer search across the web app, gateway and search service, and deleted the old one: autocomplete, search history as its own service, server-side map clustering streamed as you pan, and distance to a venue's boundary, not its pin. Around 119M requests a week.
• Loyalty was my first project, and Fresha's largest consumer release to date: points, tiers, eligibility and the wallet, schema to UI. I learned Elixir on the way.
• Hardened the shared code everyone else builds on. Made the shared Elixir libraries more resilient, including connection handling on failed health probes and converting runtime input to atoms safely (the BEAM never frees them). Built CLDR locale handling, pluralisation and TypeScript codegen into the treatment taxonomy the marketplace searches against. Wrote the organisation's supply chain standard (SHA-pinned actions, pinned toolchains, isolated installs, no fetch-and-execute), with a first-party carve-out so people could follow it.
• Reviewed 615 pull requests for other engineers, mentored people through hard problems, and gave product-level input so technical decisions matched what the business needed. Also built an internal Claude plugin marketplace, including a skill that takes a ticket to an opened pull request.

Senior Full Stack Engineer, Apolitical 2024

Key Skills: Next.js, NestJS, React, TypeScript, Kubernetes, Vite, Express, SCSS, GitHub Actions

• Built Next.js features and NestJS APIs for a move to a new architecture, and kept the existing React frontends and Express microservices running until the move was done.
• Debugged performance problems in services on Kubernetes and extended the GitHub Actions pipelines.

Senior Cloud Native Engineer, EngineerBetter 2022–2024

Key Skills: AWS, Azure, Kubernetes, Terraform, Concourse, Docker, Go, Python, CSPM, Cloud Foundry, BOSH

• I wanted to step out of frontend work and broaden my skills, so I joined a small consultancy that helps companies move their infrastructure and processes onto continuous deployment, and their software onto cloud platforms built to run it. We took large, complex enterprise projects and made them manageable, scalable and declarative, putting reproducibility and resistance to drift ahead of strict GitOps where the two disagreed.
• Wrote Kubernetes controllers in Go, and CI in Concourse, GitHub Actions and GitLab for estates where the pipeline is a large system of its own.
• Implemented Cloud Security Posture Management in several different ways for different clients. Azure Policy couldn't yet express something Credit Suisse needed for their CSPM to work. I went to Microsoft's Paddington office to make the case, and a few weeks later it could.
• Wrote Python tooling to audit code and deployments across enterprise estates too large for anyone to inspect by hand.
• Between clients, contributed to Kubernetes External Secrets Operator, mostly by pairing with less experienced engineers and bringing them on, and to Compliance Framework, an open source CSPM auditing tool that has since been retired.

Consultant Full Stack / Mobile Engineer, Superbike Factory (Freelance) 2021–2024

Concurrent with EngineerBetter and ROXi

Key Skills: React Native, TypeScript, AWS CDK, Lambda, DynamoDB, API Gateway, CloudFront, MobX-State-Tree, BitBucket Pipelines

• A former manager needed an internal Android app built quickly and for a reasonable cost, and brought me in because I was the person he trusted to get it done well. It let bike delivery drivers view their jobs, upload notes and photos, do training with quizzes and video, and by the end of the project take the customer's payment.
• I enjoyed it because it was well defined and I was building all of it, app and infrastructure. His existing systems were on AWS, so I chose CDK, Lambda, DynamoDB, API Gateway and CloudFront for the backend and helped him integrate it with the services he already had. It was good to have free rein on a greenfield project again and make something fast, efficient and cheap to run.
• The frontend is React Native with MobX-State-Tree and a thin layer of AWS Amplify.
• The BitBucket pipeline deploys the infrastructure, reads the CloudFront outputs back and builds a working app against them. Everything is derived, so the only configuration a new environment needs comes from its own variables.
• Audited the existing infrastructure code and made it more secure in several places.

Lead Developer, ROXi 2020–2022

Key Skills: Swift, Java, WebSockets, React Native, TypeScript, Astro, React, Node.js, AWS, MobX-State-Tree, Vite

• Built several key projects from scratch.
• The core product was a React Native companion app for a TV app that ran inside a browser and couldn't host any kind of daemon. I came up with having the phone run a WebSocket server and talk to the television directly over the LAN, with low latency.
• Wrote the native WebSocket transport for both platforms as React Native modules, Java on Android and Swift on iOS, and made the iOS side thread-safe with Grand Central Dispatch.
• Built internal curation tools on MobX-State-Tree, Tailwind and Vite, and a statically generated e-commerce and account servicing site in Astro when Astro was new.

Consultant Frontend Developer, Sapien Interactive (Freelance) 2019–2024

Concurrent with ROXi, EngineerBetter and Superbike Factory

Key Skills: React Native, TypeScript, Firebase, MobX-State-Tree, Node.js, WebSockets

• A former business partner brought me in to build the app for a new venture and restart an earlier project we'd worked on, in React Native, MobX-State-Tree and Firebase.
• I came to MobX-State-Tree sceptical, because I preferred the explicit, functional immutability of Redux. I approached it with an open mind, and once I understood MobX's observables and had moved the codebase from class components to functional components with hooks, wrapped in mobx-react observers, the simplicity and elegance won me over: observables for performance, mutable-style updates, flows for side effects, and very little boilerplate.

Senior Mobile Developer, Zopa Financial Services 2018–2020

Key Skills: Swift, Kotlin, React Native, TypeScript, Redux, Java, Kafka, detox

• My move into fintech, leading development of the credit card section of Zopa's app, in React Native with Redux as the data layer.
• Wrote native modules in Swift and Kotlin against Stripe's card issuing APIs while those APIs were still new.
• I learned a huge amount about React Native there. The team kept the codebase current and picked up new things like hooks as soon as they made sense, and put a heavy emphasis on well-reviewed, well-tested code, with detox and @testing-library/react-native.
• Learned the financial products in depth to be useful to the analysts and backend engineers, and pitched in on backend fixes along the way.

Open Source

Handwritten the old way, or architected by hand and written with AI: everything I make is there for anyone with the curiosity to look.

• nano-web Rust · 240+★: in-memory static file server for SPAs and static content, and what serves this site.
• jaritanet TypeScript: my own infrastructure as a single Pulumi program. It provisions a Hetzner VPS, installs k3s on it, reads the kubeconfig back as an output of the same run that consumes it, and deploys into the cluster it just built, so there's no secret round-trip and nothing for a human to rotate. It uses Cilium as the CNI so NetworkPolicies are enforced, Traefik terminating Let's Encrypt TLS over DNS-01, and a censorship-resistant proxy layer (Xray VLESS-REALITY, Hysteria2, unbound, tailscale) running as hostNetwork DaemonSets rather than systemd units, so the host itself runs k3s and sshd and nothing else. Xray owns :443 and passes unmatched traffic to Traefik, so the public site and the proxy share a port. It runs this site, Navidrome, and an MCP gateway with Hydra and Postgres behind it, with VictoriaMetrics and Grafana watching all of it. GitHub Actions previews the stack on a pull request and applies it on merge, and a scheduled job tracks upstream component versions and opens the bump itself.
• fastmail-cli Rust · 65+★: CLI and MCP server for Fastmail over JMAP, CardDAV and GraphQL, with attachment text extraction and masked email. Predates the official Fastmail MCP, largely because I knew what I wanted out of it and couldn't be bothered waiting to find out if they'd want the same.
• MCP servers in Rust: tfl-mcp, which wraps TfL's REST API into a fully associated graph. Bots love it. codeowners-lsp, mcp-gateway, caldav-cli, mainlynorfolk-mcp. All share a GraphQL transport I designed for them: one typed, introspectable graph instead of a sprawl of flat tools, so a model can find what exists and ask for exactly the fields it needs. It uses far fewer tokens, and when it fails, a model can read why.
• kōan Rust · Swift · 25★ · source: a music player and server for local and OpenSubsonic libraries, built from 25 years of messing about with music and wanting my dream app. Native SwiftUI apps for macOS and iOS link a Rust core directly, alongside a terminal UI and a server. Your DAC runs at each track's own sample rate, gapless survives you editing the queue, room and headphone correction imports from Roon, REW and AutoEQ per output, network amps get the actual file, and playback moves between devices with each one playing its own copy. It stays compatible with OpenSubsonic throughout, so every part works with the rest of the ecosystem, and its MCP server lets an assistant build a playlist and start it on your phone.
• GrogLog Swift · source: I know people who struggle with how much they drink, and I wanted them to have something completely free that helps them cut down and does more than the paid apps. No subscription, no adverts, no account and no server. It counts UK units, prices and calories from a catalogue of over 1,100 drinks, sets a gradual reduction plan within UK clinical guidance, charts progress and streaks, shows heart rate, HRV and sleep from Apple Health against the evening before, and logs from widgets and Shortcuts.
• watchwoman Rust: a drop-in watchman replacement that doesn't eat your RAM.
• blit.cc Rust: this site. A static site generator with a content-hashed asset pipeline that fails the build on an unreferenced or hand-written path, and askama_gettext, a gettext implementation for Askama covering 36 locales with CLDR plural rules, checked against CLDR at build time so a catalogue can't disagree with it silently. Nothing reaches the browser but HTML, CSS and a font. The locale picker is command/commandfor and a native <dialog>.
• pip: #789, SSL certificate verification, which shipped in pip 1.3 as the fix for CVE-2013-1629.
• Contributions elsewhere: TanStack Router (static prerendering fix, and docs), Django REST Framework (timedelta support in the JSON encoder), git-absorb (darwin arm64 build target), react-native-webview, ops (unikernel packaging fixes), go-buildpack (take the Go version from go.mod), icu_ex (compact notation and percent styles for Elixir number formatting), sorl-thumbnail, bowser.
• Earlier: xr 440+★, Ham 380+★, a PHP microframework from when that was a reasonable thing to write, subdown 19★, servers.py 13★, python-nginx 12★, redux-rx-http 12★.

Skills

Daily: TypeScript, Elixir, GraphQL, Node.js, PostgreSQL, React, Next.js, Docker, Git, GitHub Actions, Tailwind, CSS, bash/zsh, Linux, agentic AI tooling and MCP.

Strong: Rust, Go, Python, React Native, Swift, Kotlin, Java, gRPC and Protobuf, Kubernetes, Terraform, AWS (CDK, Lambda, API Gateway, DynamoDB, S3, CloudFront, Cognito, ECS/Fargate, RDS, IAM, Route53, SQS, SES, CloudWatch), Redis, Zod, Vite, esbuild, bun, Zustand, MobX-State-Tree, Redux, RxJS, WebSockets, Kafka, i18n, TDD/BDD.

Worked with: Astro, NestJS, Express, Django, Flask, Celery, Cython, Twisted, MySQL, MSSQL, MongoDB, CouchDB, Couchbase, Memcached, Pulumi, ArgoCD, Ansible, Azure and Azure Policy, Concourse, CircleCI, BitBucket Pipelines, GitLab CI, Traefik, Nginx, Apache, ZeroMQ, Socket.IO, C#, .NET, C++, C, x86 assembly, Qt, PHP, AngularJS, jQuery, SASS/LESS, Cloud Foundry, BOSH, Mesos/Marathon, unikernels, Vagrant, SVN.

Education

Full disclosure: I dropped out of Computer Science & Cybernetics at the University of Reading, despite winning various competitions for my work along the way. It wasn't for me.

Who is James?

Computers aren't a job I go to. They're part of how I'm built. I shoot photography, street portraits mostly these days, which began as urban exploration in Berlin and slowly turned the lens on the people. I cycle, and I care about the freedom it gives people. Music and audio matter to me. I go out of my way to find weird little bands nobody has told me about yet, and I would rather wander into somewhere and talk to a person than have an algorithm hand it to me. I still think technology can be the thing that gives you back control of your own existence, and people are starting to notice. So I run my own homelab and my own music collection, and I built my own audio player, because nothing this close to the heart should live at the pleasure of a large corporation. Everyone should have a choice.

I follow current affairs closely, especially where the technology is.

Less Recent Work

Senior Frontend Developer, On The Dot (formerly LastMileLink) 2017–2018

Key Skills: React, TypeScript, Redux, redux-observable, Go, Node.js, AWS Lambda, API Gateway, Apigee, Auth0, Swagger

• Part of the team that owned the frontend, mainly the allocation UI that controllers used to assign deliveries and bookings to couriers.
• Helped refactor the whole codebase onto React 16, Redux and redux-observable for side effects.
• Started taking on backend projects there, and took ownership of authentication (Auth0), authorisation (Lambda and JWT), user management, and automated API aggregation across Swagger, API Gateway and Apigee.

Lead Frontend Developer, SmartFocus 2015–2017

Key Skills: React, AngularJS, Redux, flux, Node.js, Express, WebSockets, ZeroMQ, Redis, C++, C#, .NET, Qt

• Lead engineer in the innovation and frontend teams at a London marketing technology company, building and rebuilding a large share of the frontend code and internal services.
• Architected and built three of their core products, shipped and forthcoming, in React, Redux and Node.js, and mentored the other engineers on them.
• Set patterns and practices that the wider technical team adopted.
• Took on database architecture, system design, and UX and product design wherever a problem needed it, learning whatever else it took.

Lead Frontend Developer, Bootbag 2014–2015

Key Skills: React, flux, WebSockets, CSS, HTML

• Prototyped and built a startup's frontend in React, early enough that most of the patterns didn't exist yet.

Technical Director, Links Creative 2013–2015

Key Skills: Django, PHP, AngularJS, jQuery, Node.js, Express, C#, .NET, Linux, nginx

• Technical director of a small Brighton agency. Mostly Django, AngularJS, jQuery and PHP, taking projects from ideas in clients' heads to fully developed products.

Web Developer, Freelance 2010–2013

Key Skills: PHP, Django, Flask, AngularJS, jQuery, Node.js, Linux, nginx, Apache

• Moved to Brighton and dropped myself in the deep end, learning to network, manage projects, and lean on technical skills that were improving as fast as the work demanded.

Web Developer, Primrose London 2009–2010

Key Skills: PHP, Linux, Active Directory, Git

• PHP and systems administration. Integrated the Linux servers with Active Directory and set up version control with Git.

PHP Developer / Sysadmin, The Escape Committee 2007–2009

Key Skills: PHP, MySQL, Gentoo, Linux, Apache, Asterisk

• Web development and systems administration, including working out the Asterisk phone systems.