Senior engineering staff augmentation
Tell us the role and the stack. You get senior engineers whose credentials you verify yourself — third-party certification, not a profile we wrote about ourselves — working under a written security and compliance policy you read before anyone touches your code. Two weeks inside your repository before you commit to anything.
Not sure about compliance? Speak to our security officer200+ clients work with our specialists
350+
In-house engineers. Not a freelancer network
15+ years
Delivering for clients in 30 countries
250+
Clients delivered, 3 unicorns in portfolio
4.9 / 5.0
Clutch rating · 5.0 on Goodfirms
$3M
Professional indemnity, $2M liability cover
Ratings are third-party and independently checkable. Insurance limits are per claim and apply to engagements contracted through us.
How it works
The usual version of this takes three weeks of your senior engineers' time interviewing strangers whose CVs were written by the agency sending them. We would rather you checked first and talked second.
Stack, seniority, domain, the overlap hours you need, and when you want someone starting. One form, no call required.
You get profiles, not a discovery meetingAnonymised profiles with real track records and a verification link for every certification claimed, plus our security and compliance policy and insurance certificate on request. You confirm the credential and read the policy without asking us to explain either, then interview only the people worth your time.
Documents before conversationYour codebase, your harness, your review process, at our standard rate. On day fourteen you hold three things: the merged work, a written read of your harness — what was there, what changed and why — and the measurement set up on your repository with its baseline. All three stay with you whether or not you continue.
Our standing trial policy, not a special offerWho we place
A sample of the people we place. Every detail comes from their actual record, and we confirm who is available when you send the brief. Profiles stay anonymised until an NDA is in place, and you interview them before anything is signed.
Senior Mobile Engineer
Swift & Kotlin · Banking
Five years inside one of the largest banking platform SDKs — identity, authentication, transactions and payments. Led MFA work including OTP and push approval flows, and runs security reviews against banking compliance requirements.
Request this profile →Senior Software Engineer
Rails · Legacy modernisation
Takes production Rails applications through version upgrades without disturbing live payment and booking flows. Migrated 120+ storefronts off Shopify onto a custom commerce platform.
Request this profile →QA Lead
Test strategy · Automation
Leads a ten-person QA function across manual and automation streams. Owns release readiness and go/no-go, and has built QA practices from nothing inside HIPAA-sensitive healthcare products.
Request this profile →Lead Java Engineer
Java & Spring · Distributed systems
Integrated a GDPR client module into 15 microservices on a financial services platform, enabling right-to-access and right-to-erasure workflows under EU data protection law. Engineered a Kafka topic comparison system processing 60M messages at 1M comparisons per minute, and led the migration of a 20-year-old Delphi system to Java and Spring Boot. Contributor to Hibernate OGM, Apache Ignite and Infinispan.
Request this profile →Senior Backend Engineer
Java · Payments microservices
Designed and delivered microservices for the payments domain of a banking platform carrying high-load web and mobile integrations, and migrated legacy monolithic services onto that architecture. Cut average response time by roughly a quarter through query and caching work, and made capability tests run before merge rather than after, which took the production defect rate down with it.
Request this profile →Senior Software Engineer
Java · Identity & multi-repo migrations
Owns multi-repo migrations end to end — code, CI workflows, Helm charts and integration tests. Ran a Spring Boot 4 and JDK 25 upgrade on a transaction-dispute service, then wrote the upgrade guide that sibling services were migrated against. Built a dispute-notification pipeline with retry and race-condition handling, and a transactional outbox with a Redis-based distributed lock for safe multi-pod delivery.
Request this profile →Senior iOS Engineer & Engineering Manager
Swift · Mobile practice
Led cross-functional teams of three to five engineers, brought release cycles down from four weeks to two, and raised crash-free sessions by 30% through QA automation and CI/CD. Defined the mobile standards other engineers work to — framework selection, architecture, competency matrices for iOS and Android, and a base project template for project kickoff.
Request this profile →Lead iOS Engineer
Swift & SwiftUI · E-commerce, FinTech
Led iOS for a large-scale e-commerce platform serving millions of users. Architected its multi-provider payment layer — the abstraction boundary between payment provider SDKs and business logic lets a provider be swapped without touching the UI. Chose an incremental, per-screen route through a UIKit-to-SwiftUI migration to keep regression risk off high-traffic checkout and account pages.
Request this profile →iOS Engineer
Swift · Combine · Banking
Works on authentication and authorization flows, profile management and self-service features inside a banking platform, including framework maintenance and support for its long-term-support versions. Refactored legacy code for performance and stability, and built the ML interface for a farm diagnostics product from the project's inception.
Request this profile →Android Engineer
Kotlin · Identity & security SDKs
Builds the identity and security SDKs that banks embed in their own apps — login, biometric and FIDO authentication, registration — shipping to multiple banks in production while maintaining several long-term-support versions in parallel so older deployments stay stable. Hardened on-device biometric credential storage by hashing storage keys end to end with full unit-test coverage. Earlier, eliminated more than 12,000 monthly crashes on an app with over 30M installs and took unit coverage on owned modules to 80%.
Request this profile →Senior Android Developer
Kotlin Multiplatform · Architecture
Built two Kotlin Multiplatform applications from scratch and designed the architecture for both, which took feature delivery across iOS and Android to roughly twice the pace. Developed a secure chat application on Kotlin and Jetpack Compose, running the full cycle from requirements through UI design to release, including the customer conversation.
Request this profile →Senior Android Engineer
Kotlin & Compose · Banking, Fleet systems
Built a banking client application from scratch — architecture, BFF contracts, and a component-based Compose design system with Figma token generation and theming. Also built the navigation module for a street-cleaning fleet system, with offline maps for low-connectivity operation and voice alerts for route deviation and GPS loss, and led the refactoring of its legacy codebase.
Request this profile →Tell us the stack and domain and we will come back with who actually fits, including people not listed here.
Checked, not claimed
Two things you can verify before the first call: the engineer, and the company behind them. Both come as documents you read yourself, not as assurances from a salesperson.
Some of our engineers hold Claude Certified Architect – Foundations; others hold Anthropic's course certificates: Claude 101, Claude with the Anthropic API, Claude Code in Action, Claude with Amazon Bedrock, Claude with Google Vertex AI, Introduction to Model Context Protocol, AI Fluency: Framework and Foundations, among others. The profile says which an engineer holds before you meet them.
We will not blur the two. The first is an examination by a third party — proctored at a Pearson centre against a fixed pass mark, the same exam the certified architects at the large consultancies sit. The second is completed training. Both are recorded and carry a public verification link; the proctored credential runs twelve months, and we show it only while live.
What it tells you: their AI-tooling work was examined or trained by someone other than us, and which of the two. What it does not: whether they know your stack. You check that as you always have, in your own technical interview — which this shortens, not replaces.
Company-managed devices under enforced MDM policy, access through your own connection points where you require it, and a HIPAA-ready delivery process where your sector needs one — with a security officer who answers your questionnaire rather than a sales deck that summarises it. $3M professional indemnity and $2M liability cover, under a master agreement that sets ownership, IP assignment, notice and replacement terms.
Ask for the policy, the insurance certificate and the agreement with the brief. You get the documents, not our description of them, before anyone touches your code.
Practicalities
Why senior still matters
In 2000, Steve Ballmer paced a Microsoft stage chanting developers, developers, developers until he was hoarse. He was right, and he still is. What changed is not whether you need developers — it is which ones. The craft moved: from writing every line to governing a system that writes them. That move is what separates the people below, and it is why a cheaper option often costs more.
| On the job | Traditionally | Marketplace freelancer | Our engineers |
|---|---|---|---|
| Knowing the stack | The framework, its internals, its upgrade path. | Their own toolchain. Your harness is something to get around. | The harness too — its context files, conventions, limits, and why it was built that way. |
| Reviewing code | Reading for logic, style and intent, against human habits. | If it passes CI it ships. Review is the client's problem. | Reading for the failure modes only generation produces — silent duplication, convention drift, plausible-but-wrong structure. |
| Fixing a mistake | Correct the code. The author learns and doesn't repeat it. | Correct the output. The next prompt reproduces it exactly. | Correct the code and the instruction behind it, so it stops recurring. |
| Tacit conventions | Carried in the team's head, taught by review over months. | Never learned — gone before they would have mattered. | Written into the harness, so the system holds them and new work inherits them on day one. |
| Checking the claim | A CV, references and a technical interview. | A self-written profile and badges the platform awards itself. | A third-party certification you verify yourself — proctored exam or recorded course, and the profile says which — then the same technical interview you would run anyway, with fewer strangers in it. |
| When it goes wrong | In-house. The employer carries the risk. | A platform dispute and, at best, a refund of hours. | $3M professional indemnity and $2M liability, under a contract your legal team can read. |
When not to hire us
For a bounded task with a clear finish line, they usually are — and we cost more than one, so we will say so. The difference shows up on work that has to outlive the engagement. If you would rather have that evidenced than argued, the trial sets up the measurement on your repository — duplication, review rounds and revert rate, split by author — and leaves you the baseline and the tooling. The comparison comes out of the quarter that follows, and you get it either way.
Tell us the role
Give us the shape of the work and we will come back with the two or three people who actually fit — anonymised profiles, real availability dates, and verification links you can check before you speak to anyone. If compliance is the question, tick the box below and our security officer takes the first conversation.
Thank you for contacting us
Our manager will get back to you shortly. While waiting, you may visit our portfolio.
We use cookies to make Jetruby better. By clicking "Accept cookies", you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. OK, I want to read more