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MySQL to Railway Postgres

This is an operator’s playbook for a MySQL to Railway Postgres migration. It covers the Railway-specific connection details — the public TCP proxy, self-signed TLS, and private networking — that you need to move MySQL into a Railway PostgreSQL service.

If you searched for how to migrate MySQL to Railway Postgres or move a MySQL database to Railway, the short version is: use Railway’s public proxy URL (DATABASE_PUBLIC_URL) with sslmode=require from an external host, run the migration inside Railway to avoid egress charges when you can, and let pgferry’s MySQL type mapping handle enums, sets, and unsigned integers.

What this guide is for

Section titled “What this guide is for”

Use this guide when you have a live MySQL database and want it on a Railway-hosted PostgreSQL service. It assumes you have added a Postgres database to a Railway project. For source-side behavior that is not Railway-specific, read the generic MySQL to PostgreSQL guide alongside this page.

Why use pgferry instead of generic pgloader advice

Section titled “Why use pgferry instead of generic pgloader advice”

pgloader is the usual “mysql to railway postgres” suggestion, and it falls down on real schemas:

  • No resume — a drop over Railway’s TCP proxy means restarting the whole load. pgferry checkpoints and resumes.
  • MySQL enums, sets, unsigned integers, tinyint(1), and zero dates are explicit, documented knobs in pgferry.
  • pgferry streams with chunked, parallel COPY and runs a plan preflight that surfaces skipped indexes, generated columns, and required extensions first.

Destination prerequisites

Section titled “Destination prerequisites”
  • A Railway project with a Postgres service. Default database is railway, default user is postgres.
  • The connection variables from the service’s Variables tab. Railway’s Postgres image runs as a single-tenant container, so the postgres role has broad privileges — CREATE SCHEMA, CREATE EXTENSION (for extensions whose binaries ship in the image), etc.
  • For pgvector or other non-default extensions, deploy the matching Railway template/image variant — the base image only carries the standard contrib set.
Section titled “Recommended pgferry config”
schema = "app"
on_schema_exists = "error"
unlogged_tables = false
resume = true
validation = "row_count"
chunk_size = 100000
source_snapshot_mode = "single_tx"


[source]
type = "mysql"
# dsn supplied via PGFERRY_SOURCE_DSN


[target]
# dsn supplied via PGFERRY_TARGET_DSN


[type_mapping]
tinyint1_as_boolean = false
json_as_jsonb = true
enum_mode = "check"
set_mode = "text"
sanitize_json_null_bytes = true

resume = true requires unlogged_tables = false (see the configuration reference).

Railway DSN, TLS, proxy, and networking notes

Section titled “Railway DSN, TLS, proxy, and networking notes”

Railway exposes two connection URLs on the Postgres service:

VariableHost shapeUse from
DATABASE_URL (private)postgres.railway.internal:5432Another service inside the same Railway project
DATABASE_PUBLIC_URL (public)<name>.proxy.rlwy.net:<random-port>An external migration host
  • From your laptop or any external host, use DATABASE_PUBLIC_URL. The .railway.internal host is not routable outside Railway. The public proxy port is randomly assigned — never hardcode 5432 for the external endpoint; read it from the variable.
  • TLS: Railway’s Postgres image uses a self-signed certificate. Use ?sslmode=require (encrypts the connection without certificate-chain verification). sslmode=verify-full will fail because Railway does not publish a CA for the auto-generated cert.
  • Egress: traffic through the public proxy leaves Railway’s network and counts toward egress/network billing. A multi-GB migration over the proxy can add up.
  • Private networking: if you run pgferry as a service inside the same Railway project, use DATABASE_URL (the internal host) — no egress charges, lower latency. Note the private network is IPv6-based; the Go/pgx driver pgferry uses handles this as long as the host resolves.

Example external (public proxy) target DSN:

Terminal window
export PGFERRY_TARGET_DSN='postgres://postgres:<password>@<name>.proxy.rlwy.net:<proxy-port>/railway?sslmode=require'
export PGFERRY_SOURCE_DSN='user:pass@tcp(mysql-host:3306)/source_db'

Inside Railway (same project, no egress):

Terminal window
export PGFERRY_TARGET_DSN='postgres://postgres:<password>@postgres.railway.internal:5432/railway?sslmode=require'

The private network is isolated to your Railway project, so sslmode=disable also connects internally — but Railway’s image serves SSL on the same port, so keep sslmode=require to encrypt the wire with no practical downside.

Capacity gotcha

Section titled “Capacity gotcha”

The Railway Postgres service is backed by a volume with a plan-dependent size cap, and WAL plus indexes built during the load consume extra space transiently. Pre-size or upgrade the volume before a large import so you do not run out mid-load.

Source-specific caveats (MySQL)

Section titled “Source-specific caveats (MySQL)”

Decide these on the MySQL side (full detail in the MySQL guide):

  • enum_mode / set_mode — how ENUM/SET land in PostgreSQL.
  • tinyint1_as_boolean — only if tinyint(1) means boolean.
  • widen_unsigned_integers / add_unsigned_checks — preserve unsigned ranges.
  • zero_date_mode — 0000-00-00 → NULL or error.
  • Generated columns copy as values; FULLTEXT, prefix, and expression indexes are reported and skipped.
  • ci_as_citext = true needs the citext extension (present in the base image’s contrib set).

Step-by-step MySQL to Railway Postgres migration flow

Section titled “Step-by-step MySQL to Railway Postgres migration flow”
  1. Add Postgres to your Railway project and copy DATABASE_PUBLIC_URL (or use the internal URL if running inside Railway).
  2. Confirm the volume is large enough for the dataset plus index/WAL overhead.
  3. Generate a config with pgferry wizard or start from the snippet above.
  4. Export PGFERRY_SOURCE_DSN and PGFERRY_TARGET_DSN.
  5. Run pgferry plan migration.toml and resolve every warning.
  6. Run pgferry migrate migration.toml; rerun on interruption (resume = true).
  7. Recreate views, routines, and triggers via hooks.

Validation and cutover checklist

Section titled “Validation and cutover checklist”
  • pgferry validate migration.toml re-runs validation without redoing DDL or COPY.
  • Confirm required extensions exist (and that you used the right image variant for pgvector etc.).
  • Verify the volume has headroom after the load.
  • Spot-check enum/set and tinyint(1) columns.
  • Walk the cutover checklist and first production migration checklist.

Common failures for this provider pair

Section titled “Common failures for this provider pair”
SymptomCauseFix
could not translate host name "postgres.railway.internal"Used the private host from outside RailwayUse DATABASE_PUBLIC_URL
TLS / certificate verification errorverify-full against a self-signed certUse sslmode=require
Connection refused on :5432 externallyHardcoded port instead of proxy portUse the random proxy port from DATABASE_PUBLIC_URL
No space left on device mid-loadVolume too small for data + indexesPre-size/upgrade the volume
Unexpected network billBulk load over the public proxyRun the migration inside Railway (private network)

See common failures and recovery.

Section titled “Related”