Validating a Salesforce ID: 15 vs 18 character format and the checksum

TL;DR

There are two levels.

Fix

1. There are two levels. Expected: you can confirm this matches your situation.

When to use

• You are setting up or using this Validating a Salesforce ID feature.
• The symptom matches: 15 vs 18 character format and the checksum.

When NOT to use

• Unrelated Validating a Salesforce ID issues (different feature, different failure).
• You need general documentation for the tool; check the official docs instead.

Compatibility

Reported against Validating a Salesforce ID.

Variant phrasings

15 vs 18 character format and the checksum

Why it happens

Stack Overflow question (score 37): how to validate a Salesforce record ID before sending it to the API.

Edge cases

• If your error message differs even slightly, this is probably a different issue; search the exact text.
• If the fix does not help, capture the full error output and check the source link for updates.

Stack Overflow question (score 37): how to validate a Salesforce record ID before sending it to the API. Resolved: There are two levels. First check the format with a regex: 15 or 18 alphanumeric characters. For 18-character IDs, the last 3 characters are a checksum of the first 15, so you can verify the checksum to catch typos and malformed IDs before they hit the API. Source: https://stackoverflow.com/questions/9742913/validating-a-salesforce-id