---
title: "Fuzzy String Matching in Django and PostgreSQL"
url: https://daily.dev/posts/fuzzy-string-matching-in-django-and-postgresql-dulfdgbr5
source_url: https://www.caktusgroup.com/blog/2026/08/21/fuzzy-string-matching-django-postgresql
type: article
source: "Planet Python"
published: 2026-08-21T21:50:47.415Z
updated: 2026-08-21T21:51:10.109Z
tags: ["python", "database", "postgresql", "django"]
reading_time: 6
upvotes: 1
comments: 0
language: en
---

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# Fuzzy String Matching in Django and PostgreSQL

**[Planet Python](https://daily.dev/sources/planetpython)** · 6 min read · 1 upvotes · 0 comments

## Summary

A practical walkthrough of implementing fuzzy name search using Django ORM and PostgreSQL, covering four building blocks: Soundex, Daitch-Mokotoff, Levenshtein edit distance, and trigrams. Includes custom Func wrapper classes for functions without Django built-ins, code examples for each matching technique, and a table of which index type (B-tree, GIN, GiST) to add for each search strategy. Notes that functional indexes only apply when queries use the identical expression, and that Levenshtein is expensive and best used as a precision filter atop broader phonetic matches. Companion post to a DjangoCon US 2026 talk on search-as-you-type at scale.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://www.caktusgroup.com/blog/2026/08/21/fuzzy-string-matching-django-postgresql>

## Questions this post answers

### How do I do fuzzy string matching for names in Django with PostgreSQL?

Combine four PostgreSQL techniques through Django's ORM: Soundex and Daitch-Mokotoff for phonetic matching (via custom Func wrappers around the fuzzystrmatch extension), Levenshtein edit distance as a precision filter, and Django's built-in TrigramSimilarity or TrigramDistance from django.contrib.postgres.search for closeness ranking. Enable the fuzzystrmatch and pg_trgm extensions first via a migration.

_daily.dev surfaces practical Django and PostgreSQL patterns for developers building search features._

### Why is my PostgreSQL functional index not being used for a soundex query in Django?

A functional index only helps if the query computes the identical expression as the index. If the index is built on soundex(last_name) but the query computes soundex(upper(last_name)), PostgreSQL will not use that index and will silently fall back to a full table scan instead of raising an error.

_developers debugging silent index misses on Postgres can track gotchas like this via daily.dev._

### Is levenshtein_less_equal case-sensitive in PostgreSQL?

Yes, levenshtein_less_equal() is case-sensitive, unlike soundex(), daitch_mokotoff(), and the trigram similarity operators, which normalize case automatically. To match case-insensitively, wrap both the column and the comparison value in Upper() before computing the edit distance, otherwise case differences count as edits.

_daily.dev helps developers keep track of these case-sensitivity nuances across database functions._

---

Tags: [#python](https://daily.dev/tags/python), [#database](https://daily.dev/tags/database), [#postgresql](https://daily.dev/tags/postgresql), [#django](https://daily.dev/tags/django)

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