API rombik

1. Authorization

Every request is signed with an API key (rk_…). Create one in your account — it is shown once, then only the prefix. Header (either of the two):

X-API-Key: rk_YOUR_KEY
Authorization: Bearer rk_YOUR_KEY

2. POST /render

Code → flowchart as a file. Charges 1 credit per chart (3 charts in a file — 3 credits).

JSON with code

curl -X POST https://rombik.app/api/v1/render \
  -H "X-API-Key: rk_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"code":"def f(a):\n    return a*2","lang":"python","format":"svg"}' \
  -o schema.svg

Or upload a file

curl -X POST https://rombik.app/api/v1/render \
  -H "X-API-Key: rk_YOUR_KEY" \
  -F [email protected] -F format=pdf \
  -o schema.pdf

Or from a URL

curl -X POST https://rombik.app/api/v1/render \
  -H "X-API-Key: rk_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"url":"https://raw.githubusercontent.com/user/repo/main/app.py","format":"svg"}' \
  -o schema.svg

3. render parameters

* code is required for a JSON body; when uploading a file use file.

Fields of options

Custom values (your own branch/IO words, terminators, returnWord, forEachWord, capWord, capFormat, forFormat) require active Pro on the account — otherwise 402 pro_required (the proFeatures field lists which). Toggles, locale, font, scale, figStart are free.

4. render response

By default — a file (byte stream + Content-Disposition):

HTTP/1.1 200 OK
Content-Type: image/svg+xml
Content-Disposition: attachment; filename=rombik.svg

<svg xmlns="http://www.w3.org/2000/svg" …>…</svg>

?json=1 — JSON (fields below):

{
  "format": "svg",
  "lang": "python",
  "filename": "rombik.svg",
  "encoding": "utf-8",        // or "base64" for png/pdf
  "content": "<svg …>…</svg>",
  "creditsLeft": 41
}

• format / lang — what was rendered
• filename — suggested file name
• encoding — utf-8 (svg/typst/excalidraw/json) or base64 (docx/png/pdf)
• content — the result itself (string or base64)
• creditsLeft — how many credits are left

5. JSON mode

Handy for pipelines — not a file but JSON with content. Binary formats (docx/png/pdf) come as base64.

curl -X POST "https://rombik.app/api/v1/render?json=1" \
  -H "X-API-Key: rk_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"code":"...","lang":"cpp","format":"png","scale":3}'

6. GET /me

Credit balance and Pro status by key — no browser needed.

curl https://rombik.app/api/v1/me \
  -H "X-API-Key: rk_YOUR_KEY"

Response:

{
  "email": "[email protected]",
  "name": "You",
  "credits": 42,
  "pro": true,
  "proUntil": "2026-07-01T00:00:00Z"   // "" if no Pro
}

7. Top-up

POST /topup

Hit “no credits”? Get a payment link right from a script — jarUrl already has the amount and code. Per unit (credits_unit + qty), as a pack (credits + id) or Pro (pro + id); id comes from the catalog on the site.

curl -X POST https://rombik.app/api/v1/topup \
  -H "X-API-Key: rk_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"kind":"credits_unit","qty":10}'
# → {"jarUrl":"https://send.monobank.ua/jar/…?a=30&t=rk_cr_…","amountUah":30,…}

8. Formats & credits

Formats: docx · typst · excalidraw · svg · png · pdf · json.

Each /render call = 1 credit per chart (the server renders it, so no exceptions for PNG). Top up in your account.

9. Limits & errors

Paid /render — no limit (credits bound it). Free ones (/me) — 60 requests/min per key (above → 429). Errors: {"error":"…"}.

10. Gift credits

POST /gift

Gift export credits to a friend right from a script — give their email and a quantity. It’s deducted from your balance and added to theirs (an account is created by email if needed). They get an email and an in-account notification.

curl -X POST https://rombik.app/api/v1/gift \
  -H "X-API-Key: rk_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"email":"[email protected]","qty":5}'
# → {"ok":true,"credits":37}

11. POST /render/batch

POST /render/batch

Many sources in one call — each item is code or url. Charges 1 credit per chart among successful items (balance must be ≥ the item count at least). format:"pdf" → a single multi-page PDF (one page per item); other formats → a zip with one file per item. Up to 100 items. With ?json=1 — a per-item report.

curl -X POST https://rombik.app/api/v1/render/batch \
  -H "X-API-Key: rk_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"format":"pdf","items":[
    {"url":"https://raw.githubusercontent.com/user/repo/main/a.py"},
    {"code":"def f(x):\n    return x*2","lang":"python","name":"double"}
  ]}' \
  -o project.pdf

12. rombik native format

For languages rombik does not parse (assembler, pseudocode…), or when the chart does not correspond to any code — set lang:"rombik" and put a flowchart tree into code as astJSON. The parser is skipped, but layout still adds ДСТУ shapes, the Start/End terminators, Yes/No labels and numbering. This is full manual control of the chart — Pro only (otherwise 402 pro_required). All export formats and options work as usual.

Structure: an array of functions (each → its own chart)

[{ "name": "grade", "main": true, "block": { "kind": "block", "stmts": [
  { "kind": "io", "text": "Ввід s" },
  { "kind": "if", "cond": "s >= 60",
    "then": { "stmts": [ { "kind": "io", "text": "Вивід: Залік" } ] },
    "else": { "stmts": [ { "kind": "io", "text": "Вивід: Незалік" } ] } },
  { "kind": "for", "cond": "i := 1, n",
    "body": { "stmts": [ { "kind": "call", "text": "обробити(i)" } ] } }
] }}]

Node kinds

Node fields: { kind, text?, cond?, then?, else?, body?, stmts?, jump? }. then/else/body are block nodes {"stmts":[…]} (kind may be omitted), an empty branch is {"stmts":[]}. In for the spec goes in the cond field (not text), format «var := start, end[, step]», e.g. «i := 1, n». Do not draw Start/End/Yes/No by hand — layout adds them. Validation errors come back as text (fix and retry): unknown kind, if/while/for without cond, process/io/call without text, break outside a loop, limits (≤2000 nodes, depth ≤100).

Full example — find the maximum in an array

[
  { "name": "findMax", "main": true, "block": { "kind": "block", "stmts": [
    { "kind": "io", "text": "Ввід a, n" },
    { "kind": "process", "text": "m := a[0]" },
    { "kind": "for", "cond": "i := 1, n-1", "body": { "stmts": [
      { "kind": "if", "cond": "a[i] > m",
        "then": { "stmts": [ { "kind": "process", "text": "m := a[i]" } ] },
        "else": { "stmts": [] } }
    ] } },
    { "kind": "io", "text": "Вивід m" },
    { "kind": "terminal", "text": "Повернути m" }
  ] } }
]

Call (CLI or MCP render_flowchart with lang:"rombik")

rombik render schema.json --lang rombik -f pdf -o out.pdf