Python & Django development — for product teams and agencies worldwide

Python backends that handle real traffic, scale clean, and carry the AI features you will need next.

Custom Python engineering on Django, FastAPI, and the data stack that AI runs on. We ship Python applications with p95 latency under 200 ms, 85%+ test coverage on critical paths, typed end to end with Pydantic and mypy, and an architecture ready for the RAG systems and AI workflows most products will need within the year.

1,000+
Python apps shipped since 2015
10yrs
Building with Python
4.9
Across 1,000+ reviews
200ms
p95 API latency baseline · every build
The real cost

A slow, untyped, or AI-unready Python backend is a tax you pay every quarter.

Most product teams discover their Python backend is holding the business back only after a year in production — p95 latency has crept up, the codebase has no type safety so every change is a gamble, and the AI feature the board now wants cannot be added without a rebuild. The three observations below are what we say out loud on every Python discovery call.

01

Python is not slow. Your database and your blocking calls are.

The most common objection to Python — that it is slow — barely applies to a web backend, because the request spends almost all of its time waiting on the database, not running Python. A slow Python endpoint is slow for the same reasons a slow backend in any language is slow: N+1 queries, missing indexes, no caching, and synchronous external calls made one after another. We have inherited many Python apps blamed on the language, and the cause was the database every time. Fix the queries and the same endpoint moves from a 2-second p95 to under 200 milliseconds.

02

Untyped Python is a codebase nobody can refactor safely.

Python lets you ship without type hints, and most Python codebases take that offer. The cost is invisible at first and brutal later: with no type checker, every change is a gamble, every new engineer onboards slowly, and the codebase becomes a place people are afraid to touch. Typed Python — type hints throughout, Pydantic at the edges, mypy in strict mode on every CI run — turns a gamble into a guarantee. The type checker catches the mismatch before production. It is also the foundation for reliable AI features, where the model's unpredictable output has to be parsed into a known shape before anything trusts it.

03

The Python you ship today is the foundation your AI features run on tomorrow.

Most products will need an AI feature within the next year — a search that understands meaning, an assistant, a workflow that classifies or drafts. Whether that is a clean addition or a painful rebuild is decided now, by the backend underneath. A typed, tested, well-structured Python backend lets a retrieval-augmented feature or an AI workflow be added as a service. A tangled one forces a rebuild before the AI work can even start. We build Python backends with that next step already in mind, because we also build the AI — see our AI Engineering practice.

What we build

Six kinds of Python build, each engineered to last a decade.

Django applications

Full products built on Django 5 with Python 3.12+ — SaaS platforms, marketplaces, content systems, internal tools. The Django ORM with proper eager-loading, a tightened admin your ops team can actually run, secure defaults on from day one.

FastAPI services

Lean, async, typed services for APIs, microservices, and AI backends. FastAPI on Starlette with Pydantic validation at every edge, automatic OpenAPI documentation, dependency injection, and streaming responses. The right shape for I/O-bound workloads.

Django REST Framework APIs

Production APIs for mobile apps, single-page frontends, and partner integrations — without leaving Django. DRF serializers, token and session auth, throttling, versioning, filtering, and OpenAPI schema generation built into the product backend.

AI & data backends

The Python layer AI runs on — retrieval-augmented generation, vector search, LLM integration, and the data pipelines that feed them. FastAPI, Pydantic, PostgreSQL with pgvector, the OpenAI and Anthropic SDKs behind a thin model abstraction.

Python automation & pipelines

Background processing, scheduled jobs, ETL, scraping, and data pipelines. Celery with Redis for task queues, scheduled work that runs reliably, and pipelines that move data between systems without falling over at 3 AM.

Performance & async migration

p95 latency under 200 ms, query count under 10 per endpoint, cache hit ratio above 80%. Profiled production databases, N+1 elimination, Redis caching, and WSGI-to-ASGI async migrations for the I/O-bound workloads that earn it.

Beyond the build

The work that keeps the Python backend healthy after launch.

A Python backend stays healthy only as long as someone is watching the queries, the dependencies, the security patches, and the version drift. We offer three engagement types alongside the build itself.

Python & Django migrations

Legacy Python and Django brought up to current versions. A stays-passing-the-whole-time upgrade strategy: one major version at a time, tests passing at each step, no big-bang rewrites. Python 2 to 3 migrations on older systems where they are still holding a business back.

  • Django 2.x / 3.x → Django 5.x (typical 4-10 weeks)
  • Python 2 → Python 3.12 with code modernisation
  • Legacy framework (Flask, web2py) → Django or FastAPI
  • Tests passing at every step — no big-bang rewrites

Performance audits & ongoing engineering

Monthly retainers covering security patches, Python and Django version updates, dependency upgrades, database performance monitoring, task queue health, error tracking with Sentry, slow-query log review, backup verification, and a fixed allocation of engineering hours per month.

  • Security patches · weekly cadence
  • Slow-query log review · monthly
  • Celery and worker health monitoring
  • Allocated hours: bug fixes, small features, refactors

Security audits & compliance

OWASP Top 10 audits on every build — SQL injection, XSS, CSRF, SSRF, broken access control, and the rest. The Django security checklist run before launch. Dependency vulnerability scanning with pip-audit. PCI and SOC 2 control implementation. Security is part of the build, not a fix before launch.

  • OWASP Top 10 audit on every release
  • Dependency scanning with pip-audit on every CI build
  • Django deployment security checklist · passing
  • PCI / SOC 2 control implementation
Backend & reliability scoreboard

The numbers every Python build we ship has to hit.

Every Python build is shipped against four hard targets. We measure, we tune, we re-measure. Below the line, the build is not done until each number is in the green.

01 — API latency & throughput

p95 under 200ms · p99 under 500ms · every endpoint

Measured continuously in production. p95 is the metric that matters — the median hides the slow tail, p99 is too noisy on low traffic. Healthy Python APIs hit p95 under 200 ms. Slow ones cross a second and stay there.

p50 38ms p95 92ms p99 180ms RPS 1.4k / sec Async I/O on FastAPI Eager-loaded · cached Celery: slow work offloaded UNDER SLO · GREEN
02 — Test & type coverage

85%+ tests · mypy strict clean · pytest

Test coverage on critical paths above 85%, and the whole codebase typed and checked with mypy in strict mode on every CI run. Coverage and types together are what make a Python codebase safe to refactor and safe to grow AI features on.

88% TESTS VIEWS / ROUTES 93% SERVICES 89% MODELS 85% mypy --strict · clean
03 — Security & OWASP

OWASP Top 10 passing · dependencies clean

SQL injection, XSS, CSRF, SSRF, broken access control, security misconfiguration, vulnerable dependencies — every Python build is audited against the OWASP Top 10, and pip-audit runs on every CI build.

OWASP Top 10 · passing pip-audit · 0 known vulnerabilities Django security checklist · passing
04 — Observability & uptime

Sentry · structured logs · 99.9% uptime SLA

Production error tracking on every Python build with Sentry. Structured logging that is actually searchable. Task queue health monitoring. Uptime monitoring with alerting. The team finds out about issues before customers do.

99.9 % uptime SLA MONITORED Sentry production errors ALERTING Structured searchable logs TRACEABLE
How we work

Five steps from brief to a Python backend your team can run for a decade.

The process below has stayed the same for ten years and 1,000+ Python builds. Every step is required. Skipping any one of them is how Python backends end up slow, untyped, or quietly insecure.

01

Brief and API spec

We learn the application domain, the team, the existing codebase if there is one, the integrations and third-party APIs, and whether AI or data work is in scope now or coming next. We finish with a written brief, an API specification on paper, and a data model diagram.

02

Architecture and data modelling

Database schema design with proper normalisation and indexes. The Django or FastAPI decision, or the case for both. Service-layer boundaries. Caching, queue, and auth strategy. Where a separate AI service should sit. The architecture is decided before any feature work starts.

03

Custom Django and FastAPI build

Python 3.12+ with type hints throughout and Pydantic at the edges. Django with a tightened admin, or FastAPI for the async services, or both. A pytest suite alongside the code and mypy strict in CI. Weekly demos, two-week sprints, preview deploys on every pull request.

04

Security and load testing

OWASP Top 10 audit. The Django security checklist. pip-audit for vulnerable dependencies. Load testing against expected production traffic. Real-database testing of N+1 patterns. p95 latency tuning. The team that will run the backend uses it before launch.

05

Launch, monitor, maintain

Launch checklist. Sentry error tracking live. Structured logging enabled. Task queue dashboard. Slow-query logging on. Backup verification. Uptime monitoring with alerting. Monthly maintenance from day one. Quarterly security and performance reviews.

Selected work

Python applications we have shipped across APIs, SaaS, AI backends, admin, pipelines, and search.

Six Python applications from the last 24 months. Every one passes the backend scoreboard targets, runs OWASP-clean, types clean under mypy, and a mid-level Python engineer can pick it up on day one.

Meridian Intelligence
p95: 1.3s · evals: 94% · typed ✓
AI backend · FastAPI + RAG
Stratos Platform
p95: 96ms · 87% covered · mypy ✓
Multi-tenant SaaS · Django
Frondhill Ops
p95: 64ms · 91% covered · AA
Django + DRF · ops platform
Aurora Pipeline
99.96% job success · alerted
Data pipeline · Python + Celery
Postbrew API
p95: 88ms · webhooks 99.98%
Subscription API · Django REST Framework
Chayya Search
p95: 110ms · pgvector · typed ✓
Semantic search · FastAPI + pgvector

Need a Python backend that scales clean and is ready for AI?

Send us a brief about the application, the team, and the integrations. We will come back with a free, honest plan — fixed scope, fixed targets, no slides.

Request a discovery call
Where it shows up

Four kinds of Python build, one engineering team behind them.

The same Python capability adapts to four very different surfaces. The engineering discipline stays constant; what changes is the framework, the data model, the concurrency shape, and the deployment target.

APIs & microservices

FastAPI & DRF APIs

JSON APIs for mobile apps, single-page frontends, and partner integrations. FastAPI for standalone async services; Django REST Framework when the API belongs inside a Django product. Typed, documented, rate-limited, versioned.

SaaS platforms

Django SaaS products

Multi-tenant B2B SaaS on Django — per-tenant data isolation, Stripe billing, role-based access, a tightened admin your customer-success team can use, and the ORM kept honest with eager-loading.

AI & data backends

The layer AI runs on

Retrieval-augmented generation, vector search, and LLM integration as typed FastAPI services. PostgreSQL with pgvector for retrieval, the model SDKs behind a thin abstraction, evaluations so the AI is measured rather than hoped about.

Automation & pipelines

Background & data work

Celery task queues, scheduled jobs, ETL, and data pipelines that move information between systems reliably. Idempotent, retried, monitored — the kind of work that has to run at 3 AM without anyone watching.

Client stories

Two Python engagements, and what changed for the businesses behind them.

Meridian Intelligence

B2B SaaS · Django + FastAPI AI service · 2025–2026
The situation

A Series-B analytics SaaS on a Django monolith wanted to add an AI document-search feature. The team had tried bolting an LLM call directly into a Django view. It was slow, untested, and fell over whenever the model API had a slow afternoon — and it was starting to drag the rest of the app down with it.

What we did

Built the AI work as a separate FastAPI service, typed end to end with Pydantic. Retrieval over PostgreSQL with pgvector, the OpenAI and Anthropic SDKs behind a thin model abstraction, retries and fallback, and an eval suite running in CI. The Django product stayed the product; it gained two endpoints that call the new service. Sentry and structured logging across both.

The outcome

The AI feature shipped in nine weeks. p95 on the AI endpoints settled at 1.3 seconds including model time, and the Django app's own endpoints were untouched and stayed fast. The eval suite catches answer-quality regressions before release. The team can now add AI features as services instead of fearing them.

More about Meridian Intelligence →

Stratos Platform

Multi-tenant SaaS · Django · 2024–2026
The situation

A growing B2B SaaS on a Django codebase with no type hints, partial test coverage, and a p95 that had crept from 200 ms to 1.6 seconds over two years of feature additions. Every change was a gamble; the team had slowed to a crawl because nobody could be sure what a refactor would break.

What we did

A 5-day audit: profiled the production database, mapped the slowest queries, found N+1 hot spots across 38 views. Eliminated the N+1s with select_related and prefetch_related, added 19 indexes, introduced Redis caching on hot dashboards, moved email and report generation to Celery. Added type hints across the codebase with mypy strict in CI, and a pytest suite covering critical paths.

The outcome

p95 latency moved from 1.6 seconds to 96 ms. Test coverage went from 31% to 87% on critical paths, and mypy now runs clean. By the team's own measure, engineering velocity roughly doubled — because changes had stopped being frightening.

More about Stratos →
For agencies & product teams

The Python engineering team behind the agency.

Roughly 35% of our Python work is built for other agencies, product teams, and consultancies — under their brand, against their clients' deadlines. Three partnership models, all NDA-protected, with senior Python engineers working in time zones overlapping the UK, EU, and US workday.

01 · Partnership model

White-label Python development

Your brand. Our engineers. We never appear in front of your client — all communication, deliverables, and code go out under your name. The standard model for agencies that win Python or Django projects but do not want to hire in-house Python engineering.

  • NDA & sub-contract in place before any work begins
  • Code and deliverables shipped under your brand
  • Joint Slack / email channels with your team only
  • You stay client-facing; we stay implementation-facing
Used by: digital agencies, full-service shops, consultancies
02 · Partnership model

Agency-of-record & dedicated Python pod

A pod of senior Python engineers and a project lead working as your in-house Python capacity — full-time or fractional, month-to-month or annual. The choice when Python is core to your service mix and hiring in-house is slower or more expensive than partnering.

  • Dedicated pod: 2 to 6 engineers + lead, scaled to your roadmap
  • Direct integration into your project tools (Jira, Linear, ClickUp, Asana)
  • Monthly capacity commitment; retainer or rolling SoW
  • Code ownership transferred to your repositories
Used by: full-service agencies, SaaS product teams
03 · Partnership model

Capacity overflow & sprint-by-sprint

When your in-house Python team is full and the next project cannot wait. Sprint-by-sprint engagement, no commitment beyond the current two-week sprint, ready to pick up scoped work within 5 to 7 business days from green-light.

  • Two-week minimum sprint, rolling renewal
  • Scoped fixed-price work — feature build, migration, performance pass
  • Fast spin-up: 5 to 7 business days from signed SoW
  • No long-term commitment; ramp up or down per sprint
Used by: agencies with seasonal Python demand spikes
NDA-protectedStandard NDA, sub-contract, and IP transfer in place before any work begins.
Time-zone overlapWorking hours overlap with UK mornings, the EU workday, and US afternoons every business day.
Single point of contactNamed project lead on every engagement. No agency-side account churn.
Your repos, your codeCode ownership transfers cleanly. We work in your Git, your hosting, your tooling.
Already running an agency or product team? Explore our white-label terms Start a partner conversation
Why not

Cheap Python shops and notebook-grade code vs Python done as engineering.

Three routes most product teams consider before they hire a real Python engineering team. Each makes sense for someone. None hold up under real traffic the way a properly built Python backend does.

Cheap Python shop
  • Tutorial-grade Django, no eager-loading, no caching
  • No type hints · every change is a gamble
  • p95 over 1 second under modest traffic
  • No observability · bugs found by customers
  • Cheap up-front · expensive to inherit and fix
Notebook-to-production code
  • Data-science scripts shipped as a service
  • No request handling, no input validation
  • No error handling when an API is slow or fails
  • No tests, no retries, no rate limiting
  • Works in a demo · breaks under real traffic
Custom Python at Dream Steps
  • Django / FastAPI · Python 3.12+ · modern conventions
  • Typed end to end · Pydantic · mypy strict
  • p95 under 200ms · eager-loaded · cached
  • 85%+ test coverage · OWASP audited
  • Architected so AI features plug in, not bolt on

Cheap Python is the most expensive Python.

The savings show up in month one. The cost shows up when the database falls over at 10x traffic, when a refactor breaks something nobody could see coming because there were no types and no tests, and when the rewrite finally happens 18 months later. Every cheap Python build we have inherited has cost the client more in rebuild than custom would have first time round.

A notebook is not a production service.

A Jupyter notebook is the right place to prove an idea, and a lot of Python — especially AI and data work — starts there. The mistake is shipping the notebook. A notebook has no request handling, no validation, no error handling, no retries, no observability, and no tests. It works because one person ran the cells in order on good inputs. A production service has to work when ten thousand people send bad ones.

A custom Python build does more, scales further, and carries the AI work next.

It costs more up front because that is what it costs to architect a backend with proper typing, testing, observability, and security from day one rather than retrofit them later. Three years in, the maths favours it on every axis we measure — engineering velocity, p95 latency, security posture, and whether the AI feature the business now wants is a clean addition or a rebuild.

— The honest read

Build the Python backend that fits the team in three years.

Request a Python engagement
Common questions

Questions Python buyers actually ask.

Fourteen of the most common WordPress questions, answered straight. If yours is not below, send it and we will reply with a real answer — not a sales pitch.

Why choose Dream Steps for Python development?

We have shipped 1,000+ Python applications since 2015 across Django products, FastAPI services, REST APIs, AI backends, and data pipelines. Our 40-person team of senior Python engineers, designers, and project leads in Noida, India works in time zones overlapping the UK, EU, and US workday. We hold every Python build to four hard targets: p95 API latency under 200 ms, 85%+ test coverage on critical paths, a clean mypy type check, and an OWASP Top 10 audit passing before launch. We also build the AI features most products will need next, so the backend we ship is ready for them rather than needing a rebuild.

Can you white-label Python and Django development for our agency?

Yes — roughly 35% of our Python work is built for other agencies and consultancies under NDA. Three partnership models: white-label (your brand, our engineers, fully invisible), agency-of-record (a dedicated Python pod working as your in-house capacity), and capacity overflow (sprint-by-sprint engagement when your in-house team is full). Code ownership transfers to your repositories. Time zones overlap with the UK, EU, and US workday, and we run inside your tooling — Slack, Jira, Linear, ClickUp, Asana — as standard.

Where is your Python team based?

Our entire Python engineering team is based in Noida, India — 40 people in our iThum Tower B office, founded in 2015. We work with product teams and agencies across the UK, US, Ireland, Australia, the UAE, Germany, and the Netherlands. Working hours overlap with UK mornings, the full EU workday, and US afternoons. For agency partners we run in their tooling — Slack, Jira, Linear, ClickUp, Asana — as standard.

Should I use Django or FastAPI?

Django for whole products — apps with users, an admin, content, and a database at the centre, where the batteries-included framework saves months. FastAPI for APIs and services, async and I/O-bound workloads, and AI backends, where a lean typed framework fits better. They are not really competitors, and the architecture we ship most often uses both: Django for the product, FastAPI for the focused services that need to be async and fast. We will tell you on the discovery call which one — or which combination — fits your build.

How much does a custom Python or Django build cost?

Custom Python builds range from focused FastAPI services through to full Django SaaS products and AI backends. The right scope drivers are the number of features, the user roles and permissions, third-party integrations, whether AI or data work is involved, and the team’s Python maturity. We scope every engagement against the specific brief, are competitive with established engineering rates internationally, and are honest about which features can wait until phase two.

How long does a Python build take?

A typical Django SaaS application takes 10 to 16 weeks. A FastAPI service or API for a separate frontend takes 6 to 12 weeks. A multi-tenant Django platform with billing and admin takes 14 to 20 weeks. An AI or RAG backend takes 8 to 14 weeks depending on the retrieval and orchestration complexity. We work in two-week sprints with weekly demos and a deployable staging environment from sprint one.

Will my Python application be fast?

Yes — every Python application we ship hits p95 API latency under 200 ms on real production traffic, query count under 10 per read request, and a cache hit ratio above 80% on cacheable endpoints. Python itself is rarely the bottleneck in a web request, because the request spends its time waiting on the database, not running Python. We achieve the targets through proper eager-loading, database indexing, Redis caching, task queues for slow work, async views where I/O fan-out justifies them, and a profiled production database. Performance is part of the build, not an afterthought.

Do you write typed Python?

Yes — every Python build we ship is typed end to end and checked with mypy in strict mode on every CI run. We use Pydantic for request and response validation at the edges of the system, type hints throughout the code, and we treat a type error as a build failure. Typed Python is what makes a codebase safe to refactor, and it is the foundation for reliable AI features, where the model’s output has to be parsed into a known shape before anything downstream trusts it.

Can you build a backend that's ready for AI features?

Yes — and it is one of the main reasons teams come to us for Python. Most products will need an AI feature within the next year, and whether that is a clean addition or a painful rebuild depends on the backend underneath. We build Python backends that are typed, tested, and structured so that a retrieval-augmented feature, an AI workflow, or an LLM integration can be added as a service rather than retrofitted into a monolith. For the deeper version of that work, see our AI Engineering page.

Django, FastAPI, or Django REST Framework — which do you build with?

All three, depending on what fits. Django for full products with an admin and an ORM at the centre. Django REST Framework when a Django product also needs a clean API for a mobile app or single-page frontend — it builds production APIs without leaving Django. FastAPI for standalone services, async and I/O-bound workloads, and AI backends. Many of our builds use more than one — a Django product with a FastAPI service alongside it for the AI work. We recommend the combination on the discovery call based on the product, not on fashion.

Can you build accessible Django admin and web apps (WCAG 2.2 AA)?

Yes. WCAG 2.2 AA is our baseline on every Python application’s frontend — colour contrast checked per token, full keyboard navigation, screen-reader landmarks audited, form labels reviewed, focus management on modals. We tighten the Django admin’s defaults for accessibility, and use accessible component primitives for any React or Vue frontend sitting on a FastAPI or Django REST Framework backend. Accessibility is part of the build, not a fix after launch.

Will you maintain the Python app after launch?

Yes. We offer monthly Python maintenance retainers covering security patches, Python and Django version upgrades, dependency updates with pip-audit, database performance monitoring, task queue health monitoring, error tracking with Sentry, backup verification, and a fixed allocation of engineering hours per month. For teams without a dedicated Python engineer in-house, this is how the application stays healthy, secure, and fast past month one.

Can you take over or upgrade an existing Python or Django codebase?

Yes. We regularly take over Python codebases — adding the tests, types, and observability they were missing — and run Django version upgrades, which are typically 4 to 10 week engagements depending on how far behind the codebase is. The process: audit the codebase for deprecated patterns and security gaps, add a test suite if one is missing, upgrade Django one major version at a time with tests passing at each step, update dependencies, then deploy to staging before production. We have done many of these, including Python 2 to 3 migrations on older systems.

What stack do you ship for a typical Python SaaS or AI backend?

Our default 2026 Python stack: Python 3.12; Django with Django REST Framework for product backends, or FastAPI for standalone and AI services; PostgreSQL with proper indexing, plus the pgvector extension for AI retrieval; Redis for cache, sessions, and as the Celery broker; Celery for background work; Pydantic for validation and mypy strict for type checking; pytest for tests; Sentry for error tracking; and structured logging with an observability tool. For AI backends we add the OpenAI and Anthropic SDKs behind a thin abstraction so models can be swapped. We adjust to the team and requirements, but that is what we recommend by default.

Do you build the AI features themselves, or just the backend?

Both. The Python backend is the foundation, and we also build the AI features that run on it — retrieval-augmented generation, AI workflows, and in-product LLM features — with evaluations and observability so the AI is measured rather than hoped about. This Python and Django page covers the engineering foundation; our AI Engineering page covers the AI systems, the eval methodology, and the service-level objectives in depth. Many engagements start as a Python backend and grow into AI work once the foundation is solid.

Ready when you are

Build a Python backend your team can run — and grow AI on — for a decade.

Tell us about the application, the team, the integrations, and whether AI is on the roadmap. We will come back with a written brief, a realistic build cost, and a clear set of performance, type-safety, security, and test-coverage targets we will hold ourselves to.

What to expect

A 30-minute conversation about your business, the editorial team that will run the site, and where you want to be in three years. No slide deck, no pitch.

You walk away with

A written brief naming the build scope, the performance and accessibility targets we will hold to, the timeline, and a realistic build cost.