ToolbyeBase64 Encode & Decode Tool

Troubleshoot Base64 Decode Failures

When decoding fails or previews do not render, this page helps isolate input format, prefix, and data integrity problems quickly.

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Suitable Input Types

  • Error-prone Base64 copied from logs, docs, or API responses
  • Data URL strings with unknown or suspicious MIME prefixes
  • Image Base64 blocks that fail to preview after decoding

Step-by-Step Workflow

  1. Confirm whether input is plain Base64 or Data URL and select matching mode.
  2. Decode once and inspect result; switch workspace if content type is mismatched.
  3. Fix prefix/padding/characters, then re-run until output and preview are stable.

Example Walkthrough

Fix a broken image preview payload

Input: data:image/jpg;base64,.... (fails in target app)

Action: Decode in Image workspace, verify MIME and regenerate with correct prefix.

Output: Preview displays normally and downloaded file opens correctly.

Common Issues in This Scenario

Invalid characters from rich-text copy

Pasting from chat or docs may inject punctuation and invisible characters. Recopy as plain text.

Wrong MIME causes blank preview

When MIME is incorrect, browser may reject rendering. Choose the right image type manually if needed.

Truncated payload

If source string was cut off, decode may succeed partially but output is corrupted. Compare against original length.

Related Scenarios

Use Base64 in API DebuggingConvert Images to Base64 for Inline UsageValidate Base64 Before Sharing
Open Image WorkspaceBack to Base64 Tool