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Async APIs · OpenAPI

FastAPI Development

High-performance async APIs for mobile apps, partner integrations, and AI services.

  • OpenAPI-first APIs for mobile and partner integrations.
  • Async I/O where throughput matters, sync where simplicity wins.
  • Typed Pydantic schemas and contract tests from day one.
  • Auth, rate limits, and staging load tests before partners connect.
  • Often paired with Django admin on the same product.
40+ projects since 2022 IST · daily sync NDA-ready
View featured case study
Founder-led team · Surat, India · English-first delivery
WHAT WE OFFER

What we deliver for fastapi development

Core deliverables

  • OpenAPI-first REST services
  • WebSocket & streaming endpoints
  • AI inference gateways
  • Partner developer portals
  • Load-tested production deploys

Why teams choose this engagement

  • REST or GraphQL APIs with OpenAPI documentation
  • Authentication, authorization, and admin interfaces
  • Database design, migrations, and backup strategy
  • Integration with payments, CRM, and third-party APIs
CHALLENGES

Problems we solve in fastapi development

  • Partners blocked without OpenAPI

    Mobile and integrator teams stall when endpoints ship without contracts, sandboxes, or consistent error shapes.

  • Async chosen for hype, not throughput

    Not every endpoint needs async I/O. We pick sync or async based on measured staging profiles, not blog posts.

  • Auth and rate limits added late

    Public APIs need token refresh, scopes, and throttling before partners connect production traffic.

  • Load surprises at launch

    SLA promises require staging benchmarks on critical paths. We load-test before you commit dates to integrators.

OUR APPROACH

How we build fastapi development

Founder-led engineers in Surat (IST) with morning and end-of-day updates so distributed product owners stay in the loop.

FastAPI fits partner APIs, mobile backends, and AI gateways where OpenAPI contracts and async I/O matter. We use it when Django would be heavier than the problem deserves, not because it is trendy.

Every FastAPI project we ship includes typed schemas, auth boundaries, and staging load tests before partners integrate.

Teams shipping mobile or partner-facing APIs that need speed, typing, and clear contracts.

CONTRACTS

OpenAPI before endpoints ship

FastAPI shines when partners integrate without Slack screenshots. Pydantic schemas, auth schemes, and example clients are part of delivery, not documentation debt.

  • OpenAPI published on staging from week one
  • Contract tests on pagination, errors, and auth edge cases
  • Postman collections and sandbox keys for partners
PERFORMANCE

Throughput with measured proof

We benchmark on staging before you promise SLAs. FastAPI sits behind nginx or an API gateway with shared logging and rate limits your on-call can trace.

  • Staging load profiles on hot paths before production
  • Observability hooks for latency and error budgets
  • Often paired with Django admin on the same product
INDUSTRIES

Where we apply fastapi development

Vertical experience from shipped products, not generic claims.

WHY US

Why teams choose us for fastapi development

Six reasons founders and product leads pick us over a generalist shop - scoped to how we deliver this engagement.

  • Contracts before code

    Partners get OpenAPI, sandboxes, and error shapes they can rely on.

  • Performance with proof

    Staging load tests before you promise SLAs to integrators.

  • Gateway-friendly

    FastAPI behind nginx or API gateway with shared auth and logging.

  • No trendy shortcuts

    We pick FastAPI when the problem is API-heavy, not for hype.

  • Handover that sticks

    Deploy docs and dependency hygiene so your next hire is not blocked.

  • Structured daily updates

    IST business hours with a morning check-in and EOD summary on your channel. Live sync calls scheduled at kickoff when you need them.

HONEST FIT

Is this for you?

Good fit

  • Mobile or third-party developers will consume your API.
  • You need WebSockets, streaming, or high concurrency on I/O-bound work.
  • You want OpenAPI docs your partners can trust.
  • Partners or mobile teams will integrate against your API contract.
  • You need typed schemas and auth boundaries from day one.
  • You want load tests on staging before launch traffic.

Probably not

  • Your product is CRUD-heavy with complex admin, Django may serve you better.
  • Your product is admin-heavy CRUD - Django may fit better.
  • You need a public website only, not an API product.
  • You expect daily scope changes with no trade-off conversation.
HOW WE WORK

Delivery process for fastapi development

How we deliver FastAPI services partners can integrate without surprises.

We audit existing code or map greenfield requirements - auth, data boundaries, and partner integrations first. You leave with risk priorities ranked, not a generic rewrite quote.

  1. Define the contract

    We audit existing code or map greenfield requirements - auth, data boundaries, and partner integrations first. You leave with risk priorities ranked, not a generic rewrite quote.

  2. Build and benchmark

    OpenAPI specs, error shapes, pagination, and versioning strategy agreed before migrations ship. Mobile and partner teams integrate against contracts, not tribal knowledge.

  3. Partner sandbox

    PR-first delivery with CI on every merge, integration tests on webhooks and payments, and staging sandboxes. Admin and API changes stay in the same sprint rhythm when both exist.

  4. Harden and hand off

    Permission review, secrets rotation plan, and load checks on critical paths before production traffic. Backward-compatible schema changes with rollback scripts when data is involved.

TECHNOLOGIES

Stack for fastapi development

Tools and runtimes we use on this type of engagement - chosen for production delivery, not slide-deck logos.

  • FastAPI
  • Python
  • OpenAPI
  • PostgreSQL
WORKFLOW

How we work on fastapi development

  • PR-first delivery

    Every change reviewed with CI status visible to your team.

  • OpenAPI specs

    Contract updates published when endpoints change.

  • Staging data

    Realistic fixtures for integration testing before prod.

  • Direct access

    Engineers on Slack, not account-manager relay.

DEPLOYMENT

Production discipline for fastapi development

  1. Auth hardening

    Secrets rotation and permission checks before scale. Least-privilege service accounts; no shared production keys in chat.

  2. Migration safety

    Backward-compatible schema changes with rollback scripts tested on staging. Long migrations run in phases, not as a Friday surprise.

  3. Webhook reliability

    Retries, idempotency keys, and partner sandbox tests before production traffic. Dead-letter handling documented for failed deliveries.

  4. Blue/green or canary

    Promotion strategy matched to your traffic profile and risk tolerance. Smoke tests gate every promote step.

OUTCOMES

Track record from fastapi development

Metrics from shipped products and active engagements - not slide-deck claims.

40+
APIs and backends shipped
OpenAPI
Contracts on every engagement
IST
Morning & EOD sync
NDA
Before repository access
CASE STUDIES

Proof from fastapi development

Real products we shipped for founders in the US, UK, and Europe.

Technical buyers want proof we ship APIs partners can integrate - with OpenAPI docs, staging sandboxes, and production systems still running in year three.

  • Partners can't integrate our API

    HerKey and AstroSure show production APIs with auth, webhooks, and mobile clients.

  • Worried about legacy migration

    Case studies include platforms we inherited, audited, and extended - not greenfield only.

  • Need OpenAPI discipline

    We document contracts and ship staging sandboxes before partners go live.

AstroSure.ai - SparkScribe Technologies case study AI & ML · SaaS
Consumer AI 8 months

AstroSure.ai

AI-powered astrology platform with personalized daily guidance

What they needed: The founders had a notebook demo but needed a production LLM pipeline with cost controls, human review, and staging parity before investor diligence.

Our approach: Before build, SparkScribe worked with AstroSure to translate their SaaS Product goals into an actionable plan — not an off-the-shelf template.Discovery & planningWorkshopped birth-chart, daily reading, panchang, kundli matching, and Agastya chat flows against latency …

An astrology platform powered by LLMs - personalized horoscope readings, panchang insights, and conversational guidance through a branded AI assistant.

  • 3× faster reading generation
  • 99.2% API uptime in production
  • Python
  • Django
  • OpenAI
  • PostgreSQL
  • Redis
  • React
  • AWS
View case study
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Hire us

Engagement models for fastapi development

Bring in FastAPI engineers for partner APIs, AI gateways, or high-throughput services with fixed milestones.

  • Fixed-scope project

    Discovery, written requirements, and milestone billing. Best for MVPs, redesigns, and integrations with a defined end state.

    • Duration: Phased milestones
    • Working: Sprint plan agreed upfront
    • Billing: Per milestone or phase
    • Timeline: Based on signed scope

  • Dedicated squad

    A focused engineering squad on your product: weekly demos, shared backlog, and one accountable team when scope evolves.

    • Duration: 8 hrs/day · 5 days/week
    • Working: ~160 hrs/month capacity
    • Billing: Monthly invoice
    • Timeline: Sprint-based delivery

  • Part-time retainer

    Smaller monthly hour buckets for fixes, dependency updates, and enhancements, with the same engineers when possible.

    • Duration: 4 hrs/day · 5 days/week
    • Working: ~80 hrs/month
    • Billing: Monthly retainer
    • Timeline: Ongoing support window
Mutual NDA before codebase access Morning & EOD IST sync Written scope before sprint one
RELATED SERVICES
FAQ

Questions about fastapi development

What prospects ask on a first call about this service: scope, timelines, fit, and how we work.

  • Scope & pricing
  • Delivery process
  • Handover & IP
  • NDA & quality gates
  • Written scope before sprint one milestones, owners, and what stays out of v1 are documented before build starts.
  • Weekly staging demos with the engineers writing your features, not a status deck relay.
  • Your IP in the contract code, designs, and docs transfer to you on agreed milestones.
  • Mutual NDA upfront before you share product details, credentials, or repository access.

5 questions

Do you deliver OpenAPI docs integrators can use on day one?

Yes. Contracts, auth scheme, pagination, and error shapes are agreed before endpoints ship. Sandboxes and example clients are part of delivery.

When is FastAPI a better fit than Django for our product?

When the product is API-first, async I/O matters, or partners need strict contracts. We say no to FastAPI when you mainly need admin and CRUD.

How do you load-test FastAPI before launch?

Staging profiles against realistic payloads, rate limits tuned from results, and observability before partners connect.

Can FastAPI sit behind our existing API gateway?

We deploy behind nginx or your gateway with shared auth, logging, and health checks your ops team expects.

What does handover look like for a FastAPI service?

Runbooks, env docs, OpenAPI in repo, and on-call notes for the routes that matter most.

GET STARTED

Building a FastAPI service? Let's define contracts.

Describe your consumers (mobile, partners, internal), throughput needs, and auth model. We'll propose OpenAPI-first delivery with staging load tests before go-live.

  • Partner-ready APIs with typed schemas.
  • Reply within one business day.