jackwener/OpenCLI · error · CommandExecutionError

coingecko global returned malformed JSON: ${err?.message ??

Error message

coingecko global returned malformed JSON: ${err?.message ?? err}

What it means

This CommandExecutionError is thrown when the CoinGecko /global endpoint returns an HTTP 200 response whose body cannot be parsed as JSON. The library wraps resp.json() in try/catch and rethrows with the underlying parse message. It signals an API-level response corruption problem, not a user input problem.

Source

Thrown at clis/coingecko/global.js:44

        }
        catch (err) {
            throw new CommandExecutionError(`coingecko global request failed: ${err?.message ?? err}`);
        }
        if (resp.status === 429) {
            throw new CommandExecutionError(
                'coingecko returned HTTP 429 (rate limited)',
                'Free tier allows ~30 calls/min. Wait and retry.',
            );
        }
        if (!resp.ok) {
            throw new CommandExecutionError(`coingecko global returned HTTP ${resp.status}`);
        }
        let body;
        try {
            body = await resp.json();
        }
        catch (err) {
            throw new CommandExecutionError(`coingecko global returned malformed JSON: ${err?.message ?? err}`);
        }
        const data = body?.data;
        if (!data) {
            throw new CommandExecutionError('coingecko global returned no data envelope');
        }
        const totalMarketCap = data?.total_market_cap?.[currency];
        const totalVolume = data?.total_volume?.[currency];
        if (totalMarketCap == null && totalVolume == null) {
            throw new ArgumentError(
                `coingecko has no market totals for currency "${currency}"`,
                'Use a CoinGecko-supported quote currency such as usd, cny, eur, or jpy.',
            );
        }
        return [{
            currency: currency.toUpperCase(),
            totalMarketCap: totalMarketCap != null ? Number(totalMarketCap) : null,
            totalVolume24h: totalVolume != null ? Number(totalVolume) : null,
            marketCapChange24hPct: data.market_cap_change_percentage_24h_usd != null ? Number(data.market_cap_change_percentage_24h_usd) : null,

View on GitHub (pinned to 49907e53dc)

Solutions

Retry the command after a short wait — this is usually a transient response-corruption issue.
Run the request manually (curl https://api.coingecko.com/api/v3/global) to inspect the raw body and see if it is HTML/Cloudflare content.
Add or refresh a browser-like User-Agent / use a Pro API key if Cloudflare challenges are recurring.
Check for a proxy or SSL-inspecting appliance mangling the response and bypass it.
Clear any stale DNS/VPN interference and retry from a different network.

Example fix

// caller: tolerate transient malformed responses
// before
const rows = await runCli('coingecko', 'global');
// after
let rows;
try { rows = await runCli('coingecko', 'global'); }
catch (e) {
  if (String(e.message).includes('malformed JSON')) await sleep(1000);
  rows = await runCli('coingecko', 'global');
}

Defensive patterns

Strategy: retry

Validate before calling

const ok = await fetch('https://api.coingecko.com/api/v3/ping').then(r => r.ok).catch(() => false);
if (!ok) throw new Error('coingecko unreachable right now');

Type guard

function isJsonObject(v) { return typeof v === 'object' && v !== null && !Array.isArray(v); }

Try / catch

try {
  rows = await runCli('coingecko', 'global');
} catch (e) {
  if (String(e.message).includes('malformed JSON')) {
    await new Promise(r => setTimeout(r, 2000));
    rows = await runCli('coingecko', 'global');
  } else throw e;
}

Prevention

Prefer a paid/Pro API key to avoid Cloudflare HTML challenges
Route API traffic outside of inspecting proxies
Retry with exponential backoff on parse failures
Verify connectivity with /ping before long batch runs

When it happens

Trigger: fetch succeeded (resp.ok) but resp.json() throws: the endpoint returned HTML instead of JSON (e.g. Cloudflare challenge page), a truncated/garbled body, or a proxy/gateway intercepted the response.

Common situations: CoinGecko or Cloudflare serving a bot-challenge HTML page with 200 status; corporate proxies or firewalls rewriting responses; transient network interruption truncating the body; CoinGecko maintenance returning an HTML error page.

Understand the failure class

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of jackwener/OpenCLI@49907e53dc (2026-08-29). Data as JSON: /api/errors/3ba4b8edd5668197. Report an issue: GitHub.