ChartQuery .NET SDK

The official .NET SDK for the ChartQuery chart and QR code API.

Generate chart images, diagrams, barcodes, QR codes and thermal labels on demand. PNG, SVG or PDF output.

The SDK exposes 20 typed async methods, one per documented endpoint (with required properties checked at compile time), plus a generic RequestAsync.

Requirements

• .NET 8 or newer

Installation

dotnet add package ChartQuery

Get your API key

Sign up for ChartQuery or sign in, then copy your API key from the dashboard. new ChartQueryClient() reads the CHARTQUERY_API_KEY environment variable.

Quick start

using ChartQuery;

using var client = new ChartQueryClient();
var response = await client.ChartAiAsync(new ChartAiParams { Prompt = "Monthly revenue 2026 as a bar chart: Jan 10, Feb 14, Mar 18" });
Console.WriteLine(response.Json);

Parameter classes mirror the API reference. Use response.Deserialize<MyType>() to map the JSON onto your own types.

Binary responses

Endpoints that return a file (image, PDF…) give you the bytes; IsJson tells both cases apart:

var response = await client.QrcodeAsync(new QrcodeParams { Data = "https://chartquery.com", Format = "png" });
if (!response.IsJson)
{
    await File.WriteAllBytesAsync("qrcode.png", response.Bytes);
}

Async jobs

Any call accepts is_async: true (useful past the 60-second server limit): the response is then a job_id. WaitForJobAsync polls GET /v1/jobs/{id} until a terminal status (CompletedJob, Error, NotFound, BadRequest):

var submitted = await client.ChartAiAsync(new ChartAiParams { Prompt = "Monthly revenue 2026 as a bar chart: Jan 10, Feb 14, Mar 18", IsAsync = true });
var job = await client.WaitForJobAsync(
    submitted.Json.GetProperty("job_id").GetString()!,
    onProgress: j => Console.WriteLine($"{j.GetProperty("status")} {j.GetProperty("progress")}%"));

GET or POST

Methods use GET when the endpoint supports it (query string). POST sends the same parameters as JSON:

await client.BarcodeAsync(new BarcodeParams { Data = "test" }, new RequestOptions { Method = "POST" });

Any endpoint

var response = await client.RequestAsync("GET", "/v1/usage");

Errors

try
{
    await client.ChartAiAsync(new ChartAiParams { Prompt = "Monthly revenue 2026 as a bar chart: Jan 10, Feb 14, Mar 18" });
}
catch (ChartQueryApiException exception)
{
    Console.Error.WriteLine($"{exception.StatusCode}: {exception.Message}");
}

Exception	When
ChartQueryConfigurationException	Missing API key, invalid options or unsupported method.
ChartQuerySerializationException	A required parameter is missing or a value can't be sent.
ChartQueryTransportException	Network failure or timeout.
ChartQueryApiException	Non-2xx status (StatusCode, ErrorMessage, ResponseBody, RawResponse).
ChartQueryResponseDecodingException	A success response could not be decoded.

All of them derive from ChartQueryException. Caller cancellation surfaces as OperationCanceledException.

Retries

Requests are retried up to 3 times after a network error, a 408, 500, 502, 503 or 504, or a rate limit — which the API returns as 401 (or 429) with a Rate limit exceeded message. Per-key quota errors (…: quota daily) are not retried, nor are 400, 402, 404 or client-side timeouts. The delay starts at 1 second and grows 1.5× per retry (capped at 30 seconds); a Retry-After header wins.

using var client = new ChartQueryClient(new ChartQueryClientOptions { MaxRetries = 5, RetryDelay = TimeSpan.FromMilliseconds(500) });
await client.ChartAiAsync(new ChartAiParams { Prompt = "Monthly revenue 2026 as a bar chart: Jan 10, Feb 14, Mar 18" }, new RequestOptions { MaxRetries = 0 }); // one request without retries

Batch requests

BatchAsync runs a function per item with at most 10 in flight (concurrency) and returns one BatchResult per item, in input order. A failing item never stops the others.

string[] inputs = { "Monthly revenue 2026 as a bar chart: Jan 10, Feb 14, Mar 18", "Market share as a pie chart: A 40, B 35, C 25" };
var results = await client.BatchAsync(inputs, (value, ct) =>
    client.ChartAiAsync(new ChartAiParams { Prompt = value }, cancellationToken: ct), concurrency: 5);
foreach (var result in results)
{
    if (result.Ok)
    {
        Console.WriteLine(result.Value!.Json);
    }
    else
    {
        Console.Error.WriteLine($"{inputs[result.Index]}: {result.Error!.Message}");
    }
}

Constant	Default	Description
ChartQueryClient.DefaultConcurrency	10	Tasks run at the same time by batch
ChartQueryClient.DefaultTimeout	TimeSpan.FromSeconds(120)	Request timeout
ChartQueryClient.MaxRetries	3	Retry attempts after a network error, a 408/5xx or a rate limit
ChartQueryClient.RetryBackoffFactor	1.5	Exponential backoff multiplier
ChartQueryClient.DefaultRetryDelay	TimeSpan.FromSeconds(1)	Delay before the first retry

Configuration

using var client = new ChartQueryClient(new ChartQueryClientOptions
{
    ApiKey = Environment.GetEnvironmentVariable("CHARTQUERY_API_KEY"),
    Timeout = TimeSpan.FromSeconds(60), // default 120 s
    HttpClient = myHttpClient,           // optional, you keep ownership
});

Endpoints

20 methods, generated from the OpenAPI document.

Method	HTTP	Description
BarcodeAsync	GET / POST /v1/barcode	Generate a barcode image via GET. Output: SVG (default) or PNG. Supports 25+ formats: EAN-13, Code 128, ITF-14, GS1-128, postal codes and m…
ChartAsync	GET / POST /v1/chart	Render a Chart.js image via GET. Pass the full chart object as URL-encoded JSON in query. Prefer format png for ChatGPT. POST sends the sam…
ChartAiAsync	GET / POST /v1/chart/ai	Describe a chart in plain English via GET and get a rendered image back. Powered by AI.
ChartRenderAsync	GET /v1/chart/render/{id}	Render a previously saved chart by ID. Public, no API key required. Supports URL overrides for templates (?data1=, ?labels=, ?title=…).
ChartViewAsync	GET /v1/chart/view/{id}	View a previously saved chart as an interactive HTML page. Public, no API key required. Iframe-embeddable.
DiagramAsync	GET / POST /v1/diagram	Render a diagram via GET. Use type (mermaid, d2, …), query (source code), and format=png for ChatGPT. POST uses diagram_type and diagram_so…
DiagramAiAsync	GET / POST /v1/diagram/ai	Describe a diagram in plain English via GET and get a rendered image back. Powered by AI.
DiagramRenderAsync	GET /v1/diagram/render/{id}	Render a previously saved diagram by ID. Public, no API key required. Supports ?format= and ?query= overrides.
DiagramViewAsync	GET /v1/diagram/view/{id}	View a previously saved diagram as an HTML page. Public, no API key required. Iframe-embeddable with inline SVG rendering.
JobsAsync	GET /v1/jobs/{id}	Poll the status, progress (0–100) and result of a job started with is_async=true. Polling is free. Poll until status is terminal: Completed…
LabelAsync	GET / POST /v1/label	Preview a thermal label via GET. Pass the same label object as a URL-encoded JSON string in query. Inside that JSON, text items use content…
LabelCompileAsync	POST /v1/label/compile	Compile a label to printer commands (tsc, zpl, epl, …). POST width, language, and elements. Text uses content and size (1-10), not text or…
LabelConvertAsync	POST /v1/label/convert	Convert printer commands from one language to another. POST source, from, and to. from is the source language (tsc, zpl, epl, …). to is the…
LabelParseAsync	POST /v1/label/parse	Parse printer commands into structured elements. POST source and language (tsc, zpl, epl, …).
LabelRenderAsync	GET /v1/label/render/{id}	Render a previously saved label by ID. Public, no API key required. Supports ?format= override.
LabelValidateAsync	POST /v1/label/validate	Validate printer commands. POST source (the raw commands) and language (tsc, zpl, epl, …).
LabelViewAsync	GET /v1/label/view/{id}	View a previously saved label as an HTML page. Public, no API key required. Iframe-embeddable with inline SVG rendering.
QrcodeAsync	GET / POST /v1/qrcode	Generate a styled QR code via GET. Output: SVG (default) or PNG. Supports dot styles, gradients, custom corners and all QR versions.
StatsAsync	GET /v1/stats	Infrastructure health for an engine or endpoint over the last hour. Not scoped to your account or tenant. Enabled per account: HTTP 403 mea…
UsageAsync	GET /v1/usage	Return this account's Chartquery usage and credit balance. No body. Requires an API key.

All ChartQuery SDKs

SDK	Package	Install
Node.js	@chartquery/sdk	npm install @chartquery/sdk
Python	chartquery	pip install chartquery
Go	chartquery-go	go get github.com/chartquery/chartquery-go
.NET	ChartQuery	dotnet add package ChartQuery
Ruby	chartquery	gem install chartquery
PHP	chartquery/sdk	composer require chartquery/sdk
Java	chartquery-java	build from source, see its README
CLI	@chartquery/cli	npm install -g @chartquery/cli
MCP server	@chartquery/mcp	npx -y @chartquery/mcp

License

MIT — see LICENSE.