SwapSQL uses real database engines to avoid common migration pitfalls
Most MySQL-to-PostgreSQL converters use text replacement and break on edge cases. SwapSQL uses a sandboxed database engine for conversion, claiming guaranteed-valid output for both migration…
Most MySQL-to-PostgreSQL converters use text replacement and break on edge cases. SwapSQL uses a sandboxed database engine for conversion, claiming guaranteed-valid output for both migration directions.
The Answer Up Front
SwapSQL is for developers performing one-off or infrequent database migrations between MySQL and PostgreSQL who need a reliable conversion. Its free tier is generous enough for many small-to-medium projects. You should skip it if you need a continuous data synchronization or replication pipeline; this is a tool for converting static dump files, not for live data streams. The bottom line is that SwapSQL’s architecture, which uses real database engines for the conversion, is fundamentally more robust than the common regex-based alternatives.
Methodology
This v0 review is based on the founder's technical blog post describing SwapSQL, published in June 2026. We are analyzing the claims made about the tool's architecture and its handling of specific migration edge cases. The tool versions cited by the founder are MySQL 8.0 and PostgreSQL 16. This review covers the described conversion process, the list of supported type mappings, and the free tier limitations.
What is not covered is an independent, hands-on benchmark. We have not uploaded a custom SQL dump to verify the output's correctness against a known-brittle schema. All statements about the tool's behavior are based on the founder's public claims at dev.to/hamidi_rasim_695ebc2f47a5/why-most-mysql-to-postgresql-converters-break-and-how-real-engines-fix-it-3nn4. Independent benchmarks are pending.
What It Does
A sandbox, not a script
The core difference in SwapSQL is its approach. Instead of parsing a .sql file with regular expressions to swap syntax, it automates a full database restore-and-backup cycle. The process, as described by the founder, is:
- Upload a source database dump (e.g., from MySQL).
- SwapSQL loads this dump into a temporary, isolated sandbox running the actual source database engine (MySQL 8.0).
- It then reads the schema and data from the live database catalog and converts it to the target engine's format.
- Finally, it exports a clean, valid
.sqlfile from the target database engine (PostgreSQL 16).
This engine-to-engine method is designed to eliminate the syntax and data integrity errors common with text-based conversion.
Handles MySQL to PostgreSQL edge cases
The founder highlights several specific failures of regex-based tools that SwapSQL claims to solve. These include correctly handling MySQL's 0000-00-00 zero dates (which PostgreSQL rejects), converting AUTO_INCREMENT columns to proper PostgreSQL sequences with the counter correctly set, mapping ENUM columns, and managing differences in quoting (backticks vs. double quotes) and character sets.
Supports PostgreSQL to MySQL conversion
SwapSQL also handles the less-common reverse migration from PostgreSQL to MySQL. The founder provides a clear mapping for PostgreSQL types that lack a direct MySQL equivalent:
| PostgreSQL | MySQL | Notes |
|---|---|---|
uuid |
CHAR(36) |
gen_random_uuid() maps to (uuid()) |
jsonb |
JSON |
Queryable with MySQL JSON functions |
arrays |
JSON |
Stored as JSON arrays |
timestamptz |
DATETIME(6) |
Converted to UTC, microsecond precision kept |
identity/serial |
AUTO_INCREMENT |
Counter continues from highest existing ID |
The tool reportedly validates this output by loading it into a real MySQL server before providing the download link.
What's Interesting / What's Not
The most interesting aspect of SwapSQL is its architectural choice. Opting for a stateful, engine-based conversion over a stateless text-parsing script is the correct engineering decision for this problem. It trades the implementation simplicity of regex for the correctness that only a real database engine can guarantee. The founder's claim that the output is
The investor read
SwapSQL is a textbook example of a successful solo-founder, product-led tool. It addresses a narrow, technically challenging, and painful problem for a large developer audience. Its market (one-off database migrations) is likely too small and episodic for venture scale, making it an unlikely candidate for large investment. However, as a bootstrapped or small-scale business, it's highly attractive. The key insight is the architectural decision to use real database sandboxes over fragile text parsing. This signals a broader trend in developer tools: users are willing to pay for tools that replace brittle, ad-hoc scripts with robust, stateful, and correct solutions, even for seemingly simple tasks. Its success is a bet on engineering quality over market size.
Pull quote: “The bottom line is that SwapSQL’s architecture, which uses real database engines for the conversion, is fundamentally more robust than the common regex-based alternatives.”
Every claim ties to a primary source. See our methodology.