API Documentation

cURL examples, full endpoint reference, and copy-paste prompts for AI agents. First conversion in under 5 minutes.

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Core

Endpoints

Converters

Options Reference

Archives (14)

Audio (38)

Documents (26)

Ebooks (7)

Fonts (13)

Images (62)

Video (10)

On This Page

Base URL
Authentication
Using an AI agent?
Quickstart
Two ways to integrate
Raw API
CLI wrappers
Rate limits
Response times & storage
Processing times
File retention
Supported Formats
Images (62)
Documents (26)
Audio (38)
Video (10)
Ebooks (7)
Fonts (13)
Archives (14)

Convert.FAST API

Convert files between 200+ formats with one HTTP request. Built for AI agents and server-side integrations.

Free to start — Sign up and get 500 Pro credits that never expire. No credit card required. Have your API key and first conversion running in under 5 minutes.

Base URL

https://api.tools.fast

Authentication

Pass your key in X-Fast-Api-Key.

X-Fast-Api-Key: fast_prod_...

All endpoints require a valid API key.

The API is designed for server-side integrations. Browser-based requests are restricted to first-party origins — call the API from your backend.

Using an AI agent?

Copy-paste this into Claude Code, ChatGPT, Cursor, or any AI coding assistant:

Download the Convert.FAST skill and reference docs, then use them to complete my task:

curl -fsSL https://convert.fast/SKILL.md -o SKILL.md
mkdir -p reference && curl -fsSL https://convert.fast/api/docs.md -o reference/docs.md
curl -fsSL https://convert.fast/convert.fast.sh -o convert.fast.sh && chmod +x convert.fast.sh

Read SKILL.md to understand how to use the Convert.FAST API.

Download the Convert.FAST skill and reference docs, then use them to complete my task:

Invoke-RestMethod "https://convert.fast/SKILL.md" -OutFile SKILL.md
New-Item -ItemType Directory -Force reference | Out-Null
Invoke-RestMethod "https://convert.fast/api/docs.md" -OutFile reference/docs.md
Invoke-RestMethod "https://convert.fast/convert.fast.ps1" -OutFile convert.fast.ps1

Read SKILL.md to understand how to use the Convert.FAST API.

Reference doc sizes — the snippets above download docs.md (~21.7k tokens, core API pages). For every page including per-converter details use docs-all.md (~101k tokens). See For AI Agents for details.

Your agent downloads a skill guide, the core API reference, and a CLI wrapper, then converts files autonomously. Set TOOLS_FAST_API_KEY as an environment variable, or lock your API key to your IP address and pass it directly to the agent — see For AI Agents for full setup.

Quickstart

Convert.FAST uses an async 3-step flow: submit → poll → download.

The cURL examples use jq for JSON parsing.

API_KEY="fast_prod_your_key_here"

# 1) Submit — returns job ID
JOB_ID=$(curl -sS -X POST "https://api.tools.fast/convert" \
  -H "X-Fast-Api-Key: $API_KEY" \
  -F "file=@photo.heic" \
  -F "targetFormat=jpg" | jq -r '.id')

# 2) Poll — wait for completion
while true; do
  RESPONSE=$(curl -sS "https://api.tools.fast/convert/job/${JOB_ID}" \
    -H "X-Fast-Api-Key: $API_KEY")
  STATUS=$(echo "$RESPONSE" | jq -r '.status')
  [ "${STATUS}" = "Succeeded" ] && break
  [ "${STATUS}" = "Failed" ] || [ "${STATUS}" = "Canceled" ] && exit 1
  sleep 1
done

# 3) Download
FILENAME=$(echo "$RESPONSE" | jq -r '.output.fileName')
curl -sS "https://api.tools.fast/convert/job/${JOB_ID}/download" \
  -H "X-Fast-Api-Key: $API_KEY" \
  -o "./${FILENAME}"

See Getting Started for the complete walkthrough with cURL, PowerShell, and CLI wrapper examples.

Two ways to integrate

Raw API

Submit, poll, download — the standard integration path. Full control for custom integrations and SDKs.

POST /convert with multipart form data (file, targetFormat).
GET /convert/job/{id} until terminal status.
GET /convert/job/{id}/download to retrieve output.

CLI wrappers

Lightweight CLI wrappers that handle submit, poll, and download in one command. For scripts, CI/CD, and LLM agents.

curl -fsSL https://convert.fast/convert.fast.sh -o convert.fast.sh && chmod +x convert.fast.sh
./convert.fast.sh photo.heic jpg

Invoke-RestMethod "https://convert.fast/convert.fast.ps1" -OutFile convert.fast.ps1
./convert.fast.ps1 photo.heic jpg

Rate limits

API access requires Pro credits — available pay-as-you-go or via subscription. Signing up free grants 500 Pro credits immediately, enough to get started. Each account can have up to 18 jobs queued + running at a time — submitting beyond this limit returns 429 with a Retry-After header. Up to 6 of those jobs will run concurrently; additional jobs stay queued until a slot opens. See Rate Limits for details.

Response times & storage

Processing times

Most image conversions complete in 1-3 seconds. Document conversions (PDF, DOCX) typically take 3-10 seconds depending on page count. Audio transcription may take longer depending on duration. Poll GET /convert/job/{id} at 1-2 second intervals for images, 3-5 seconds for documents.

File retention

Output files are available for download for 1 hour after job completion, then automatically deleted. After that, GET /convert/job/{id}/download returns 410 Gone. To clean up immediately after downloading, call DELETE /convert/job/{id} — this removes the job and its output files from our servers right away.

Webhooks — receive a POST notification when a job completes instead of polling. Pass webhookUrl and webhookSecret when submitting a job. See Webhooks for the full guide.

Supported Formats

170 converters across 7 categories. POST /convert with targetFormat — the API resolves the correct converter automatically. For live costs, limits, and options, call GET /convert/conversions.

Images (62)

avif→{gif,jpg,png,webp}, bmp→{jpg,png}, cr2→{jpg,png}, cr3→{jpg,png}, gif→{avif,jpg,png,webp}, heic→{avif,jpg,png,webp}, ico→png, jpg→{avif,ico,png,webp}, lottie→{apng,gif,jpg,png,webm,webp}, nef→{jpg,png}, pict→{avif,bmp,jpg,pdf,png,tiff,webp}, png→{avif,ico,jpg,webp}, psd→{jpg,png}, raw→{avif,jpg,png,webp}, svg→{jpg,png}, tgs→{apng,gif,jpg,png,webp}, tiff→{jpg,pdf,png}, webp→{avif,gif,jpg,png}

Documents (26)

bank-statement→excel, doc→{pdf,pdfa}, docx→{epub,md,pdf,pdfa}, jpg→pdf, md→pdf, pdf→{docx,jpg,md,pdfa,png}, png→pdf, pptx→{jpg,pdf,pdfa,png}, rtf→pdf, word→{jpg,pdf,pdfa,png}, xlsx→{pdf,pdfa}

Audio (38)

aac→{mp3,opus}, audio→{epub,markdown,pdf,srt,txt,vtt,word}, flac→{mp3,opus,wav}, m4a→{mp3,opus}, m4b→{m4a,mp3,ogg,wav}, mp3→{aac,m4a,ogg,opus,wav}, ogg→{mp3,opus}, opus→{aac,flac,m4a,mp3,ogg,wav}, paf→{mp3,wav}, wav→{flac,mp3,opus}, wma→{mp3,wav}

Video (10)

avi→{mp3,wav}, mkv→{mp3,wav}, mov→{mp3,wav}, mp4→{mp3,wav}, webm→{mp3,wav}

Ebooks (7)

azw3→epub, epub→{azw3,docx,kepub,mobi}, mobi→epub, pdf→epub

Fonts (13)

otf→{ttf,woff,woff2}, ttc→ttf, ttf→{otf,woff,woff2}, woff→{otf,ttf,woff2}, woff2→{otf,ttf,woff}

Archives (14)

7z→{iso,tar,zip}, rar→{iso,tar,zip}, tar→{iso,zip}, tar-bz2→zip, tar-gz→zip, zip→{iso,tar,tar-bz2,tar-gz}

Getting Started

# Convert.FAST API

Convert files between 200+ formats with one HTTP request. Built for AI agents and server-side integrations.

> **Free to start** — [Sign up](https://accounts.tools.fast/account/register) and get 500 Pro credits that never expire. No credit card required. Have your API key and first conversion running in under 5 minutes.

## Base URL

`https://api.tools.fast`

## Authentication

Pass your key in `X-Fast-Api-Key`.

```http
X-Fast-Api-Key: fast_prod_...
```

All endpoints require a valid API key.

The API is designed for **server-side integrations**. Browser-based requests are restricted to first-party origins — call the API from your backend.

## Using an AI agent?

Copy-paste this into Claude Code, ChatGPT, Cursor, or any AI coding assistant:

### cURL
```text
Download the Convert.FAST skill and reference docs, then use them to complete my task:

curl -fsSL https://convert.fast/SKILL.md -o SKILL.md
mkdir -p reference && curl -fsSL https://convert.fast/api/docs.md -o reference/docs.md
curl -fsSL https://convert.fast/convert.fast.sh -o convert.fast.sh && chmod +x convert.fast.sh

Read SKILL.md to understand how to use the Convert.FAST API.
```

### PowerShell
```text
Download the Convert.FAST skill and reference docs, then use them to complete my task:

Invoke-RestMethod "https://convert.fast/SKILL.md" -OutFile SKILL.md
New-Item -ItemType Directory -Force reference | Out-Null
Invoke-RestMethod "https://convert.fast/api/docs.md" -OutFile reference/docs.md
Invoke-RestMethod "https://convert.fast/convert.fast.ps1" -OutFile convert.fast.ps1

Read SKILL.md to understand how to use the Convert.FAST API.
```

> **Reference doc sizes** — the snippets above download `docs.md` ({{core-docs-tokens}}, core API pages). For every page including per-converter details use `docs-all.md` ({{all-docs-tokens}}). See [For AI Agents](for-ai.md) for details.

Your agent downloads a skill guide, the core API reference, and a CLI wrapper, then converts files autonomously. Set `TOOLS_FAST_API_KEY` as an environment variable, or lock your API key to your IP address and pass it directly to the agent — see [For AI Agents](for-ai.md) for full setup.

## Quickstart

Convert.FAST uses an async 3-step flow: **submit → poll → download**.

> The cURL examples use [jq](https://jqlang.org/) for JSON parsing.

```bash
API_KEY="fast_prod_your_key_here"

# 1) Submit — returns job ID
JOB_ID=$(curl -sS -X POST "https://api.tools.fast/convert" \
  -H "X-Fast-Api-Key: $API_KEY" \
  -F "file=@photo.heic" \
  -F "targetFormat=jpg" | jq -r '.id')

# 2) Poll — wait for completion
while true; do
  RESPONSE=$(curl -sS "https://api.tools.fast/convert/job/${JOB_ID}" \
    -H "X-Fast-Api-Key: $API_KEY")
  STATUS=$(echo "$RESPONSE" | jq -r '.status')
  [ "${STATUS}" = "Succeeded" ] && break
  [ "${STATUS}" = "Failed" ] || [ "${STATUS}" = "Canceled" ] && exit 1
  sleep 1
done

# 3) Download
FILENAME=$(echo "$RESPONSE" | jq -r '.output.fileName')
curl -sS "https://api.tools.fast/convert/job/${JOB_ID}/download" \
  -H "X-Fast-Api-Key: $API_KEY" \
  -o "./${FILENAME}"
```

See [Getting Started](getting-started.md) for the complete walkthrough with cURL, PowerShell, and CLI wrapper examples.

## Two ways to integrate

### Raw API

Submit, poll, download — the standard integration path. Full control for custom integrations and SDKs.

1. `POST /convert` with multipart form data (`file`, `targetFormat`).
2. `GET /convert/job/{id}` until terminal status.
3. `GET /convert/job/{id}/download` to retrieve output.

### CLI wrappers

Lightweight CLI wrappers that handle submit, poll, and download in one command. For scripts, CI/CD, and LLM agents.

```bash
curl -fsSL https://convert.fast/convert.fast.sh -o convert.fast.sh && chmod +x convert.fast.sh
./convert.fast.sh photo.heic jpg
```

```powershell
Invoke-RestMethod "https://convert.fast/convert.fast.ps1" -OutFile convert.fast.ps1
./convert.fast.ps1 photo.heic jpg
```

## Rate limits

API access requires Pro credits — available [pay-as-you-go or via subscription](https://accounts.tools.fast/pricing). Signing up free grants 500 Pro credits immediately, enough to get started. Each account can have up to **{{pool-max-queued}} jobs queued + running** at a time — submitting beyond this limit returns `429` with a `Retry-After` header. Up to **{{pool-max-running}}** of those jobs will run concurrently; additional jobs stay queued until a slot opens. See [Rate Limits](rate-limits.md) for details.

## Response times & storage

### Processing times

Most image conversions complete in 1-3 seconds. Document conversions (PDF, DOCX) typically take 3-10 seconds depending on page count. Audio transcription may take longer depending on duration. Poll `GET /convert/job/{id}` at 1-2 second intervals for images, 3-5 seconds for documents.

### File retention

**Output files are available for download for 1 hour after job completion, then automatically deleted.** After that, `GET /convert/job/{id}/download` returns `410 Gone`. To clean up immediately after downloading, call `DELETE /convert/job/{id}` — this removes the job and its output files from our servers right away.

**Webhooks** — receive a POST notification when a job completes instead of polling. Pass `webhookUrl` and `webhookSecret` when submitting a job. See [Webhooks](webhooks.md) for the full guide.

## Supported Formats

Copied.