Convert RST to HTML API

Convert RST to HTML in three requests

Authenticate with a bearer key from your backend (never ship the key to the browser). Submit the conversion, upload the file to the presigned URL, poll until it is done, and download the result.

curl

# 1. Submit the conversion
curl -X POST https://hushvert.com/api/v1/conversions \
  -H "Authorization: Bearer $HUSHVERT_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{ "pair": "rst-to-html", "bytes": '$(wc -c < input.rst)' }'
# -> { "jobId": "...", "uploadUrl": "...", "pollUrl": "/api/v1/conversions/..." }

# 2. Upload the file to the presigned uploadUrl
curl -X PUT "$UPLOAD_URL" --data-binary @input.rst

# 3. Poll until done, then download
curl https://hushvert.com/api/v1/conversions/$JOB_ID \
  -H "Authorization: Bearer $HUSHVERT_KEY"
# -> { "status": "done", "downloadUrl": "...", "expiresAt": "..." }
curl -o output.html "$DOWNLOAD_URL"

Node.js

import { readFile, writeFile } from 'node:fs/promises'

const KEY = process.env.HUSHVERT_KEY
const bytes = await readFile('input.rst')

// 1. Submit
const submit = await fetch('https://hushvert.com/api/v1/conversions', {
  method: 'POST',
  headers: { authorization: `Bearer ${KEY}`, 'content-type': 'application/json' },
  body: JSON.stringify({ pair: 'rst-to-html', bytes: bytes.byteLength }),
}).then((r) => r.json())

// 2. Upload to the presigned URL
await fetch(submit.uploadUrl, { method: 'PUT', body: bytes })

// 3. Poll until done
let job
do {
  await new Promise((r) => setTimeout(r, 1500))
  job = await fetch(`https://hushvert.com${submit.pollUrl}`, {
    headers: { authorization: `Bearer ${KEY}` },
  }).then((r) => r.json())
} while (job.status !== 'done' && job.status !== 'failed')

// 4. Download
const out = await fetch(job.downloadUrl).then((r) => r.arrayBuffer())
await writeFile('output.html', Buffer.from(out))

Python

import os, time, requests

KEY = os.environ["HUSHVERT_KEY"]
data = open("input.rst", "rb").read()

# 1. Submit
submit = requests.post("https://hushvert.com/api/v1/conversions",
    headers={"Authorization": f"Bearer {KEY}"},
    json={"pair": "rst-to-html", "bytes": len(data)}).json()

# 2. Upload to the presigned URL
requests.put(submit["uploadUrl"], data=data)

# 3. Poll until done
job = {}
while job.get("status") not in ("done", "failed"):
    time.sleep(1.5)
    job = requests.get(f"https://hushvert.com{submit['pollUrl']}",
        headers={"Authorization": f"Bearer {KEY}"}).json()

# 4. Download
out = requests.get(job["downloadUrl"]).content
open("output.html", "wb").write(out)

Limits and pricing

Free per month	50 conversions per account, then pay per use from account credits.
Max file size	50 MB
Privacy	Input deleted the moment the conversion finishes; output kept about an hour, then deleted.

See the full request, error codes, and idempotency reference on the API keys page, and the plans on pricing.

Why an API for this?

Document interchange between markup formats needs pandoc and, for some targets, a LaTeX toolchain. The API keeps that toolchain installed and current so you call one endpoint instead of shipping it.

Everything a browser can do (images, HEIC, audio, archives, PDF page operations) runs free and on-device in the open-source @hushvert/engine SDK - no upload, no key. This API is only for RST to HTML and the other server-only formats.

What is RST?

reStructuredText (RST) is the plain-text markup of the Python documentation world: the language Sphinx reads to build the docs for thousands of projects. Like Markdown it is readable raw, but its directive syntax expresses richer structure (tables, cross-references, admonitions) that Markdown leaves to extensions.

What is HTML?

HTML (HyperText Markup Language) is the language of web pages, and as a document format it has one superpower: every device with a browser can display it, no installation required. As a conversion target it captures a document's structure (headings, paragraphs, lists, tables, emphasis) in clean, inspectable markup that can be styled, pasted into a CMS or read as-is.

RST to HTML API FAQ

How do I convert RST to HTML with an API?

Send a POST to /api/v1/conversions with the pair and the byte count, upload the file to the presigned URL it returns, then poll until the job is done and download the result. It is three short requests; full code is above in curl, Node, and Python.

Why not just convert RST to HTML myself?

You can, if you want to run and maintain pandoc with the matching readers and writers (and sometimes a LaTeX stack). Document interchange between markup formats needs pandoc and, for some targets, a LaTeX toolchain. The API keeps that toolchain installed and current so you call one endpoint instead of shipping it.

What does it cost?

Every account gets 50 free conversions per month across all of its keys. Beyond that, the API draws on account credits, billed per conversion. Everything a browser can do is free and keyless in the open-source SDK.

What happens to my file?

The file uploads over an encrypted connection. The input is deleted the moment the conversion finishes; the converted output is kept for about an hour so you can download it, then deleted too.

Can my AI agent do this conversion?

Yes. The @hushvert/mcp Model Context Protocol server gives Claude Code, Cursor, and other agents a convert_file tool over this same API, so an agent can run the conversion in one call.

RST to HTML conversion API