Senior Python Backend Architect – Real-Time Data at Scale

Block MB; Greater London; On-site; GBP 90,000 - 130,000; Full time

Job summary

Block MB is seeking senior Python backend engineers to own data-heavy query and search systems at scale in a fast-growing data intelligence platform. You will build production APIs in Python/FastAPI and optimize queries on billions of records.

You'll shape the data layer, own the query language, and collaborate across teams while mentoring juniors. Experience with ClickHouse, PostgreSQL, and large datasets is essential, with a bias toward fast, reliable analytics.

Qualifications

• > Strong Python backend experience in recent roles (FastAPI or async frameworks).
• > Built/owned data-heavy backends serving hundreds of millions to billions of records.
• > Designed or owned search/aggregation layers (Elasticsearch/OpenSearch/ClickHouse).
• > Deep SQL and Postgres skills with performance improvements.

Responsibilities

• <b>The core scope</b> is data-heavy backend systems and the query and search infrastructure.
• <b>Scale</b> with billions of rows, fast filtering and aggregation.
• <b>Production APIs</b> in Python/FastAPI powering client features.
• <b>Data pipelines</b> integration to make new data queryable quickly.

Skills

Python back-end

Data-heavy systems

Query/Search infra

Postgres optimization

Production APIs

Leadership

LLMs / AI

ClickHouse

TypeScript basics

Tools

ClickHouse

PostgreSQL

Elasticsearch/OpenSearch

FastAPI

Job description

Block MB is seeking senior Python backend engineers to own data-heavy query and search systems at scale in a fast-growing data intelligence platform. You will build production APIs in Python/FastAPI and optimize queries on billions of records.

You'll shape the data layer, own the query language, and collaborate across teams while mentoring juniors. Experience with ClickHouse, PostgreSQL, and large datasets is essential, with a bias toward fast, reliable analytics.