Full-Stack AI Product Engineer Early-Stage, Path to Salary

• Product & Engineering
• Remote UK / Europe
• Full-time

Posted 17 October 2026

Join Sendblox at an early stage and help own the technical future of the product. Build across frontend, backend, AI workflows and integrations, bring remaining features to market, and help create the internal tools that make the team faster as the company grows.

Sendblox is building a smarter way for businesses to run personalised outreach at scale.

Our platform combines AI, CRM connectivity, messaging channels and automation to help SMEs and SMBs create more relevant, individual communication without losing the human touch.

We are looking for a hands-on Full-Stack AI Product Engineer who wants to join early, take real ownership and help shape both the product and the technical direction of the company.

This is not a narrow frontend or backend role.

You should be a coder first, comfortable moving across the full stack, working with modern AI-assisted development tools and taking features from idea through to production.

You will help own the Sendblox platform, bring remaining features to market, improve reliability and performance, and build new internal tools that help us move faster.

What you’ll do

• Own and evolve the Sendblox technical platform

• Build and improve both frontend and backend features

• Take product ideas from concept through to production

• Help complete and launch remaining Sendblox capabilities

• Maintain and improve existing integrations and services

• Build new CRM, messaging and workflow integrations

• Work with AI and agentic frameworks to create smarter product experiences

• Improve platform reliability, performance and scalability

• Debug and resolve production issues

• Improve deployment, monitoring and development workflows

• Build internal tools that help the company operate faster and more efficiently

• Work closely with the founder on product direction and technical priorities

• Help shape the long-term technical architecture as Sendblox grows

Technical experience

You should be comfortable working across a modern full-stack environment and have practical experience with several of the following:

• React / modern frontend frameworks

• TypeScript / JavaScript

• Firebase

• Firestore

• Google Cloud Platform

• Cloud Run

• Serverless services and APIs

• Stripe and subscription/payment integrations

• Webhooks

• Twilio

• SendGrid

• REST APIs

• CRM integrations

• Authentication and permissions

• AI APIs and LLM integrations

• Agentic AI frameworks

• AI-assisted coding tools

• Production deployment and debugging

Experience with Google Cloud and Firebase is particularly important.

You should also be comfortable learning new services quickly rather than being limited to one specific technology stack.

AI-first engineering

Sendblox is being built in an AI-first way.

We are looking for someone who is comfortable using AI coding tools to work faster, prototype quickly and reduce unnecessary engineering overhead.

That does not mean relying blindly on AI-generated code.

You should still be a strong engineer who understands:

• architecture

• code quality

• security

• reliability

• debugging

• data models

• API design

• performance

• maintainability

AI should make you faster, not replace engineering judgement.

Product and design mindset

We do not want someone who sees engineering as separate from the product.

You should have a good sense of:

• product usability

• interface quality

• visual consistency

• interaction design

• simplicity

• aesthetics

You do not need to be a designer, but you should recognise when something feels polished versus unfinished.

The ideal person can take a rough idea, understand what the user needs and turn it into something that feels complete.

Who we’re looking for

This role would suit someone who:

• is a coder by trade

• enjoys working across the full stack

• likes building rather than just maintaining

• is comfortable with ambiguity and early-stage products

• wants ownership rather than a narrowly defined ticket queue

• enjoys experimenting with new technology

• can work independently

• has strong problem-solving skills

• wants to help shape a product rather than simply implement somebody else’s specification

• enjoys creating internal tools as well as customer-facing products

• cares about both how something works and how it feels

Startup experience is useful but not essential.

What matters more is that you can build, ship and take responsibility for what you create.

How the role works

This is an early-stage opportunity.

At the moment, Sendblox is still building its commercial base, so this role initially needs to be flexible and voluntary / contribution-based rather than a traditional salaried engineering position.

The intention is very clear:

As Sendblox generates sustainable revenue, the role should move into paid part-time or full-time work and ultimately a well-paid salaried position for the right person.

We are looking for someone who sees value in joining early, helping build the platform and becoming an important part of the company as it grows.

This is not intended to remain an unpaid role indefinitely.

Why join now?

Because there is still a lot to shape.

You will have the opportunity to:

• take real ownership of the Sendblox product

• influence technical architecture

• help define how AI is used across the platform

• bring major features to market

• build new tools and internal products

• work directly with the founder

• shape engineering practices from an early stage

• grow into a senior and well-paid technical role as the business scales

You will not simply be joining a large engineering organisation and working through somebody else’s backlog.

You will be helping create the thing.

How to apply

Send us a short introduction covering:

• your full-stack engineering experience

• the technologies you work with most

• your experience with Google Cloud, Firebase and Stripe

• any work with AI, LLMs or agentic systems

• examples of products or systems you have built

• links to GitHub, portfolio or previous work where appropriate

• why you are interested in joining an early-stage product and helping shape it from the ground up

How to apply

Apply on this page. Share your CV or a link to your work, and we'll take it from there. Apply for Full-Stack AI Product Engineer Early-Stage, Path to Salary

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