[GH-ISSUE #16506] issue: SSE comments are not ignored and cause JSON.parse() to error. #72537

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GiteaMirror · 2026-05-13T04:36:36-05:00

GiteaMirror commented

2026-05-13 04:36:36 -05:00

Originally created by @CrushedAsian255 on GitHub (Aug 11, 2025).
Original GitHub issue: https://github.com/open-webui/open-webui/issues/16506

Check Existing Issues

I have searched the existing issues and discussions.
I am using the latest version of Open WebUI.

Installation Method

Docker

Open WebUI Version

v0.6.21

Ollama Version (if applicable)

No response

Operating System

macOS

Browser (if applicable)

No response

Confirmation

I have read and followed all instructions in README.md.
I am using the latest version of both Open WebUI and Ollama.
I have included the browser console logs.
I have included the Docker container logs.
I have provided every relevant configuration, setting, and environment variable used in my setup.
I have clearly listed every relevant configuration, custom setting, environment variable, and command-line option that influences my setup (such as Docker Compose overrides, .env values, browser settings, authentication configurations, etc).
I have documented step-by-step reproduction instructions that are precise, sequential, and leave nothing to interpretation. My steps:
Start with the initial platform/version/OS and dependencies used,
Specify exact install/launch/configure commands,
List URLs visited, user input (incl. example values/emails/passwords if needed),
Describe all options and toggles enabled or changed,
Include any files or environmental changes,
Identify the expected and actual result at each stage,
Ensure any reasonably skilled user can follow and hit the same issue.

Expected Behavior

Open WebUI ignores SSE comments and keeps waiting for the model to respond.

Actual Behavior

Open WebUI tries to interpret SSE comments as JSON objects, causing it to error when receiving the completion from certain providers.

Steps to Reproduce

Add a provider to Open WebUI that uses SSE comments (OpenRouter)
Start a completion that has high TTFT (like a reasoning model that doesn't return reasoning tokens)
Wait for it to respond.

Logs & Screenshots

Uncaught SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

Additional Information

To prevent connection time-outs, some providers (notably DeepSeek and OpenRouter) send SSE 'comments'. These comments are formatted as an SSE event with an empty field name (: OPENROUTER PROCESSING or : keep-alive). These are not JSON objects and so cause an error if attempted to be read as a JSON object.

Originally created by @CrushedAsian255 on GitHub (Aug 11, 2025). Original GitHub issue: https://github.com/open-webui/open-webui/issues/16506 ### Check Existing Issues - [x] I have searched the existing issues and discussions. - [x] I am using the latest version of Open WebUI. ### Installation Method Docker ### Open WebUI Version v0.6.21 ### Ollama Version (if applicable) _No response_ ### Operating System macOS ### Browser (if applicable) _No response_ ### Confirmation - [x] I have read and followed all instructions in `README.md`. - [x] I am using the latest version of **both** Open WebUI and Ollama. - [x] I have included the browser console logs. - [x] I have included the Docker container logs. - [x] I have **provided every relevant configuration, setting, and environment variable used in my setup.** - [x] I have clearly **listed every relevant configuration, custom setting, environment variable, and command-line option that influences my setup** (such as Docker Compose overrides, .env values, browser settings, authentication configurations, etc). - [x] I have documented **step-by-step reproduction instructions that are precise, sequential, and leave nothing to interpretation**. My steps: - Start with the initial platform/version/OS and dependencies used, - Specify exact install/launch/configure commands, - List URLs visited, user input (incl. example values/emails/passwords if needed), - Describe all options and toggles enabled or changed, - Include any files or environmental changes, - Identify the expected and actual result at each stage, - Ensure any reasonably skilled user can follow and hit the same issue. ### Expected Behavior Open WebUI ignores SSE comments and keeps waiting for the model to respond. ### Actual Behavior Open WebUI tries to interpret SSE comments as JSON objects, causing it to error when receiving the completion from certain providers. ### Steps to Reproduce 1. Add a provider to Open WebUI that uses SSE comments (OpenRouter) 2. Start a completion that has high TTFT (like a reasoning model that doesn't return reasoning tokens) 3. Wait for it to respond. ### Logs & Screenshots `Uncaught SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data` ### Additional Information To prevent connection time-outs, some providers (notably DeepSeek and OpenRouter) send SSE 'comments'. These comments are formatted as an SSE event with an empty field name (`: OPENROUTER PROCESSING` or `: keep-alive`). These are not JSON objects and so cause an error if attempted to be read as a JSON object.

GiteaMirror added the bug label 2026-05-13 04:36:36 -05:00

GiteaMirror closed this issue

2026-05-13 04:36:37 -05:00

GiteaMirror commented

2026-05-13 04:36:39 -05:00

@CrushedAsian255 commented on GitHub (Aug 11, 2025):

Edit: Didn't realize 0.6.22 just released. Attempting to reproduce.

@CrushedAsian255 commented on GitHub (Aug 11, 2025): Edit: Didn't realize 0.6.22 just released. Attempting to reproduce.

GiteaMirror commented

2026-05-13 04:36:39 -05:00

@tjbck commented on GitHub (Aug 13, 2025):

Unable to reproduce here, keep us updated (with more details)!

@tjbck commented on GitHub (Aug 13, 2025): Unable to reproduce here, keep us updated (with more details)!

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Reference: github-starred/open-webui#72537