What is a replace background API?

A replace background API is a web service that automatically swaps the background of an image with a new one. You send a source image (product, person, or scene) plus a target background, and receive a composited image with the subject placed in the new environment — with adapted lighting, shadows, and color temperature for a natural result. Used by AI headshot platforms, ecommerce brands, and ad teams to generate background variations at scale.

How does AI background replacement work?

The pipeline runs subject extraction (removing the original background), edge refinement (clean boundaries around hair, fabric, and transparent objects), and compositing with the new background — adjusting lighting direction, shadow placement, and color temperature so the subject looks like it was photographed in the new scene.

Does it work on transparent, reflective, or complex subjects?

Yes. The pipeline handles hair, fabric, glass, jewelry, bottles, and other intricate subjects. Edge detection preserves fine details like stray hairs and glass rims, and shadow/reflection rendering accounts for transparent and reflective materials so the composite looks natural on the new background.

What kind of backgrounds can I swap in?

Any image you own or have a license for — studio backdrops, lifestyle scenes, outdoor environments, branded backdrops, or custom hex color backgrounds. JPEG, PNG, or WebP up to 4096x4096 pixels are supported as background inputs.

Do I need rights to the background image I use?

Yes. Use backgrounds you own, have licensed, or are in the public domain — your own brand photography, stock imagery you've purchased, or AI-generated backgrounds are the safest options. Avoid using a competitor's scene or copyrighted imagery as a background, as that can create IP issues even after compositing.

Does it adjust lighting to match the new background?

Yes. The composited subject adapts to the lighting conditions of the new background. Highlights, shadows, and color temperature are adjusted automatically so the final result looks natural — not pasted-in.

Does it preserve natural shadows?

Yes. The API generates new shadows appropriate for the new background's lighting direction and intensity. You can opt to keep soft shadows for lifestyle shots or hard shadows for studio looks.

Does my subject stay exactly the same as the original?

Yes. Only the background is replaced — your subject's pixels are preserved. Same lighting on the subject, same textures, same colors. Only edge anti-aliasing and new-scene shadows are re-rendered so the subject integrates naturally with the new background. Critical for product photography where subject fidelity matters.

How much does the replace background API cost?

$0.48 per image with simple fixed pricing. Sign up and get $10 in free GPU credits to try it out. Contact us for volume pricing on bulk workloads.

Can I process images in bulk?

Yes. Batch endpoints with async webhook delivery. Process thousands of images with different backgrounds per job — ideal for AI headshot platforms, catalog rollouts, and campaign variations.

How fast is the replace background API?

Typical response times are under 5 seconds for standard resolution images. Built for production workloads with consistent latency at scale.

What image formats are supported?

JPEG, PNG, and WebP. Output format depends on the solution.

Typical response times are under 5 seconds for standard resolution images.

How does pricing work?

Simple fixed per-call pricing. No GPU costs, no infrastructure to maintain.

Live

On-Model / FashionProduct Imagery

Unlimited background variations at production scale

Replace Background API

Swap backgrounds in any image. Place products, people, or fashion shots in any environment with adapted lighting and shadows — one API call.

Get API access

Start with $10 in free GPU credits on signup — no commitment

Before

After

Rated 5/5 by early access developers

BetterPic·Read case study

BetterPic uses Runflow’s Replace Background API to generate studio, casual, and outdoor background variations for AI headshots at scale.

<5s

Average processing time

$0.48

Per image, fixed pricing

4096px

Max resolution supported

Any scene

Custom backgrounds or presets

How it works

No pipeline to build, no models to configure.

Send image + new background

Pull a source image and a background image (or preset). The subject is the foreground; the background defines the new scene.

AI composites the result

Runflow's pipeline extracts the subject, refines edges, and composites it onto the new background with adapted lighting, shadows, and color temperature.

Get your result

Receive the composited image with natural-looking background replacement. Re-run with different backgrounds to generate variations — each call is $0.48/image.

Swap to any scene, with a single call

Send a source image and a background — studio, lifestyle, outdoor, branded, or custom. The API handles subject extraction, edge refinement, and compositing so the result looks like the subject was photographed in the new environment, not pasted in.

Any background image or preset accepted

Automatic subject extraction with clean edges

Handles hair, fabric, and transparent objects

Lighting, shadows, and color adapt automatically

The composited subject adapts to the lighting conditions of the new background. Shadow direction, intensity, and color temperature adjust so the result is naturally integrated — no hard cut-outs, no lighting mismatches.

Shadow direction and intensity matched to new scene

Color temperature aligned across subject and background

Reflections and highlights adjusted for realism

Built for B2B workloads at scale

Generate hundreds of background variations per subject in a single batch job. Whether you're an AI headshot platform generating studio/casual/outdoor options per user, or a catalog team producing regional campaign variants, the API is built for production volume.

Batch processing with async webhooks

Same subject, unlimited background variations

Consistent output quality at any volume

One photo, unlimited environments

Skip reshoots, virtual staging vendors, and manual compositing pipelines. Generate campaign imagery across markets, seasons, and platforms from a single source photo — at $0.48/image.

Market-specific backgrounds for localized creative

Seasonal and platform-specific variations

One source photo, infinite output options

Replace background for every visual workflow

From AI headshots to ad creative. Swap backgrounds naturally at production scale.

AI Headshot Platforms

Swap studio, outdoor, and casual backgrounds per AI-generated headshot. Offer users multiple scene variations per generation at zero incremental cost. Think: BetterPic, HeadshotPro, Aragon.

Ecommerce Product Shots

Place products in lifestyle settings for enhanced listing imagery. Generate A+ content and campaign variations without physical staging. Think: Amazon A+, Shopify Plus, BigCommerce stores.

Fashion & Apparel Catalogs

Put on-model shots in studio or lifestyle backgrounds. Generate lookbook variations and seasonal refreshes without reshoots. Think: Zara, H&M, ASOS, Uniqlo.

Ad Creative & Campaign Teams

Generate campaign imagery with market-specific backgrounds. One product hero, localized for every region and platform. Think: Meta Ads, Google Shopping, TikTok Ads.

Real Estate & Virtual Staging

Replace skies, change seasons, or stage empty rooms with furnished backgrounds. Magazine-ready listing photos at scale. Think: Zillow, Airbnb, Compass, Redfin.

Creator Tools & Social Platforms

Power background-swap features for creator products. Let users drop themselves into any environment with one API call. Think: Canva, Later, Buffer, Unfold.

“

Replace Background is a favorite among our B2B customers. Companies use it everywhere — AI headshot platforms swapping in studio backgrounds, catalog teams generating lifestyle variations, ad platforms localizing creative for different markets. It's the kind of feature that just works, at any scale.

Thibaut Hennau

CEO, BetterPic

Simple, per-image pricing

One price per swap. No GPU fees, no infrastructure to manage.

$0.48/image

Fixed pricing for replace background.

One API call per background swap. Generate unlimited variations from a single source — no setup fees, no surcharges.

$10 in free GPU credits on signup

Any background image or preset supported

Adapted lighting, shadows, and color temperature

Up to 4096x4096px resolution

Batch processing with async webhooks

Under 5 seconds processing time

Get API access

Build vs. buy

Build your own

Weeks to ship

Subject extraction + compositing + lighting + shadow generation + batching

Runflow API

$0.48/image

One API call, production-ready, under 5 seconds

Processing large volumes?Contact for volume pricing

Your data stays yours

Images are processed in isolated environments with automatic cleanup. Zero data retention by default.

SOC 2 Type II

ISO 27001· In progress (Q3 2026)

GDPR

SOC 2 Type II compliant.

AES-256 encryptionIsolated processingEU data residency available

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Frequently asked questions

Generate unlimited background variations at production scale.

One API call. $0.48/image. Place any subject in any environment. Start with $10 in free GPU credits on signup.

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