json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0) — how to fix

Traceback (most recent call last):
  File "app.py", line 5, in <module>
    data = response.json()
requests.exceptions.JSONDecodeError: Expecting value: line 1 column 1 (char 0)
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Quick fix: Print what you are parsing: print(repr(response.text[:500]), response.status_code). Empty body or HTML means the request failed (check status, URL, auth headers). For files, make sure you don't read the file twice and that it isn't empty. Use json.load(f) for file objects, json.loads(s) for strings, and fix single quotes or trailing commas in hand-written JSON.

What it means

The JSON parser looked for a value ({, [, ", a number, true, false, null) and found something else. The position tells you a lot:

• line 1 column 1 (char 0) — the input is empty or starts with something that isn't JSON (<html>, Internal Server Error, a BOM).
• A later position — the input started as JSON but contains invalid syntax there.

Always look at the raw input first:

print(response.status_code, response.headers.get("Content-Type"))
print(repr(response.text[:500]))

Cause 1: the HTTP response is not JSON

The server returned an error page, a redirect to a login page, a 204 No Content, or a rate-limit message. response.json() doesn't check the status code.

import requests

r = requests.get(url, headers={"Accept": "application/json"}, timeout=10)
r.raise_for_status()                 # raises on 4xx/5xx instead of a confusing JSON error
if not r.content:
    data = None
elif "application/json" in r.headers.get("Content-Type", ""):
    data = r.json()
else:
    raise ValueError(f"Expected JSON, got: {r.text[:200]!r}")

Common reasons for HTML instead of JSON: wrong URL (missing /api/ prefix), missing or expired auth token, http:// redirecting to https://, or Cloudflare/bot protection. Look up the status code in the HTTP status codes reference.

Cause 2: the file is empty or already read

with open("data.json") as f:
    print(f.read())       # consumes the file
    data = json.load(f)   # reads "" -> Expecting value char 0

Read once, or f.seek(0) before parsing. Also check the file isn't 0 bytes (ls -l data.json) — e.g. it was opened with "w" and truncated by a crashed write.

Cause 3: json.loads on a file path or json.load on a string

json.loads("data.json")      # parses the literal text "data.json" -> error

Use json.load(open(path)) for files and json.loads(text) for strings.

Cause 4: not actually JSON (Python repr, single quotes, comments)

str(dict) produces {'a': 1, 'b': True}, which is not JSON. Single quotes, True/None, trailing commas and // comments are all invalid:

json.loads("{'a': 1}")   # Expecting property name enclosed in double quotes

Produce JSON with json.dumps() instead of str(). If you must read Python literals, use ast.literal_eval(text). Paste the text into the JSON formatter to see exactly where it breaks.

Cause 5: BOM or JSON Lines

A UTF-8 BOM at the start gives Unexpected UTF-8 BOM or Expecting value. Open with encoding="utf-8-sig".

A .jsonl / NDJSON file has one object per line; parsing it as a whole gives Extra data. Parse line by line:

with open("data.jsonl", encoding="utf-8") as f:
    rows = [json.loads(line) for line in f if line.strip()]

Last updated 2026-11-05.