Tonic Fabricate vs Mockaroo (vs Seedfast): A Test Data Generator Comparison

The Tonic Fabricate vs Mockaroo comparison usually starts as a price check, and price is the wrong place to start. The two tools don't really compete. Mockaroo is a web form that exports a flat CSV; Tonic Fabricate is an AI chat-UI that builds a connected, relational dataset. Choosing on row caps or monthly cost skips the only question that decides it: does your test data need to be flat columns, or a relational graph with valid foreign keys?

This page weighs the two on what a real database demands — foreign keys, schema-awareness, and whether the tool can run in CI — then adds a third shape neither quite covers: a live-schema CLI, for when the data has to land in Postgres with relationships intact.

Use Mockaroo for flat, single-table mock data — define columns in a web form, export CSV/JSON/SQL, free up to 1,000 rows. Use Tonic Fabricate for AI-driven, schema-aware relational data in a chat UI — a $29/month Plus plan (as of June 2026) plus per-turn token metering. If your data has to satisfy foreign keys in a live Postgres database straight from a CLI, neither fits cleanly — and that's the gap a live-schema generator like Seedfast fills.

Mockaroo and Tonic Fabricate get shelved together because both say "test data" on the box. Under the hood they barely overlap.

Mockaroo is a column-level generator. You open a web form, add fields, pick a type for each from a large library — name, email, country, a regex, a custom list — and export the result as CSV, JSON, SQL, or Excel. There's nothing to install and you're done in a minute. What Mockaroo won't do is model your database: each table comes out on its own, with no notion that your orders rows point at real customers. (Its separate REST mock-API product is a frontend tool, and a different conversation entirely.)

Tonic Fabricate works the other way around. Tonic.ai's synthetic-data product — distinct from Tonic Structural, their production de-identification platform — Fabricate is schema-aware. You describe the dataset in a chat UI, or point it at a live database to model from existing structure ("Live Connect"), and it generates relationally intact data without copying production. For a large model it can draft a multi-step generation plan before building, and it targets Postgres, MySQL, Oracle, Databricks, and more.

What decides it is shape, not quality: flat columns, or a connected relational dataset with valid foreign keys.

The table scores each tool on workflow criteria — the things that decide whether it survives in a real Postgres project — rather than the column-type counts most comparisons lead with. Faker appears as one row because it shows up on these lists; it's a library, not a schema-aware generator.

One row there is deliberately a loss for Seedfast — multi-database breadth — and the per-tool detail below covers the trade-offs the checkmarks flatten.

If you already know your data has foreign keys and lives in Postgres, Seedfast seeds valid relational rows straight from your live schema in one command — start a free 30-day trial (no card), or run your first seed in about two minutes.

Mockaroo is the right choice when your data is flat and you don't care about relationships. It's genuinely good at what it was built for: a realistic-looking CSV in under a minute, no install, a huge type library, and a free tier that covers a quick demo. For a single throwaway table, a fixture file, or a CSV to paste into a spreadsheet, it's hard to beat — and its no-install web UI reaches a first result faster than a tool you have to install, Seedfast included. That speed-to-first-row is a real advantage, worth being honest about.

Pricing is published and flat (verified June 2026 against mockaroo.com/pricing). The free tier caps generation at 1,000 rows per file plus 200 API requests per day. Paid tiers scale by file size: Silver $60/year (100,000 rows per file), Gold $500/year (10M rows), and Enterprise $7,500/year (unlimited). If your problem is raw volume, that's the right axis to price on.

Where it stops: Mockaroo produces flat rows and doesn't connect to your database — it exports, you import. It doesn't enforce cross-table foreign-key integrity, so a relational schema with twenty tables turns into a manual job: export each table, then stitch the foreign keys together by hand. More free rows won't fix that; it's structural. The Mockaroo alternative comparison covers the relational, CLI-driven path off that wall.

Tonic Fabricate is the right choice when you want AI-assisted, schema-aware generation in a polished browser experience and you're comfortable handing the tool your schema — by describing it, connecting once, or pasting it. Fabricate produces relationally intact data without production access, and the chat-driven workflow is pleasant if you like iterating on a prompt in a UI.

Its real edge over Seedfast is breadth. Fabricate generates into and exports from far more than Postgres — MySQL, Oracle, Databricks, plus formats like Parquet and Avro — where Seedfast stays Postgres-focused. If your work spans several database engines or needs exotic export targets, a Postgres-only tool simply won't match that reach.

Pricing is a credit-and-token model (per Tonic's pricing, as of June 2026): a free tier with $10/month in credits, a Plus plan at $29/month including $25/month in credits, then per-turn metering — roughly $0.17 for a standard turn and $0.37 for a complex, multi-table one. The structure matters more than the exact cents: every run past your credits adds variable cost.

Where it stops: Fabricate can connect to a live database, but it runs as a web and chat agent. There's no one-command CLI step that reads your schema and seeds inside a pipeline on every run — its CLI loads already-generated data. The per-turn meter also makes per-pipeline cost harder to forecast than a flat plan. The full breakdown, with the pricing math, is the Seedfast vs Tonic Fabricate comparison.

Seedfast fills the gap between them: relational data, generated from your live schema, run as a CLI command against a real database. Seedfast gives you the relational dataset the way a CI pipeline wants it — one command, a connection string, no UI to click through and no schema to re-describe.

seedfast seed --scope "100 accounts with transactions and varied balances"
  → Connected to PostgreSQL
  → Found 34 tables, 67 foreign keys
  → Generating data...
  → Done. Seeded 12,847 rows in 6.3s

Seedfast connects to a live Postgres database and reads the schema — tables, columns, foreign keys — on every run, which is what that "34 tables, 67 foreign keys" line reports. It walks the foreign-key graph, inserts parents before children in topological order, and resolves circular foreign keys that have no valid linear insert order at all. When a migration adds a column or a table, the next run picks it up with nothing to reconfigure — there's no seed script to maintain. The same command runs as one step in CI/CD database seeding, and the MCP tool (seedfast_run) lets AI coding agents like Claude Code, Cursor, and Windsurf seed a database directly.

Seedfast's honest limits: it's Postgres-focused, so it doesn't target SQL Server, MySQL, or Oracle as first-class databases, and Fabricate's breadth wins there. It generates data from your schema rather than masking a production dataset; if you need a de-identified copy of real rows, that's the data seeding tools category instead. And for a one-off flat CSV, it won't beat Mockaroo's zero-install head start.

Best for: teams on Postgres (plain PG, Supabase, Neon, RDS) who need valid relational data in CI — from the live schema, without maintaining a seed script, on flat pricing instead of a per-turn meter.

Seedfast and Mockaroo sit on opposite sides of the relational line, and the comparison usually comes up when a Mockaroo-CSV workflow hits a wall. Mockaroo is the right tool while the data stays flat — one table, independent rows, exported to a file. The moment a child row has to reference a parent that actually exists, you're doing the database's job by hand.

Seedfast reads the real foreign-key graph from your Postgres database and produces rows that already satisfy it, so there's no manual stitching and no import-order spreadsheet. Switching costs little: you point the CLI at the same database instead of importing a file, describe the scenario instead of defining columns, and drop the export-and-reconcile step entirely. Mockaroo still wins for an instant, no-install, single-table CSV; Seedfast wins the moment the data has to be relational and valid against a live schema. The Mockaroo alternative page walks through that migration table by table.

Not across tables. Mockaroo is a column-level generator: it produces flat rows one table at a time and doesn't enforce cross-table foreign-key integrity. You can fake a reference inside a single dataset, but nothing guarantees a child row points at a parent that exists in a separate export. A relational schema needs you to reconcile the keys by hand, or a schema-aware generator that walks the graph for you.

Seedfast is flat monthly pricing with no usage meter: a 30-day free trial (no card), then Basic at $8/month, Premium at $12, and Premium+ at $16 for larger databases and CI setups. Every paid plan includes unlimited seeds; the tiers differ by how many tables you seed at once (25 to 100), not by rows or tokens (as of June 2026; see pricing). Mockaroo bills by file size per year, and Tonic Fabricate meters per generation turn.

There are no seed scripts or factory code to port — a Mockaroo workflow has none to begin with. You point the Seedfast CLI at the same Postgres connection string, describe the scenario instead of defining columns in a form, and drop the export-then-import step. Your schema stays exactly as it is; Seedfast reads it directly on each run.

Yes. Mockaroo is a web form and Tonic Fabricate is a chat UI (with SDK and API access); both are web-first. Seedfast runs as a CLI command against a live Postgres connection string, reads the schema itself, and runs natively in CI. It's also MCP-native, so AI coding agents can seed a database directly. Fabricate still wins on multi-database breadth if you're not Postgres-only.

Only partially. Mockaroo exports a file that some later step has to import, so it isn't a seeding step itself. Tonic Fabricate offers an SDK, an API, and a CLI that loads already-generated data, but the generation happens in its web and chat agent. Seedfast is built to run as one CLI command inside CI, reading the live schema and seeding on every build.

The decision comes down to shape. Flat data you need right now? Mockaroo's web form is fast and free up to its cap. AI-driven relational data through a UI, across several database engines? Tonic Fabricate is a real option. Relational data that lives in Postgres and has to regenerate in CI without a script to maintain — that's the gap the first two leave open.

Seedfast fills it: point the CLI at your live Postgres connection, describe the scenario, and get connected, referentially valid data in one command. Pricing is flat — a free 30-day trial, then $8–$16/month with unlimited seeds and no per-token meter. Run your first seed in about two minutes, or see pricing.

Related guides:

• Best Postgres Test Data Generator — the wider Postgres buyer comparison
• Mockaroo Alternative — the relational, CLI path off a column generator
• Seedfast vs Tonic Fabricate — the deep one-on-one, with the pricing math
• Data Seeding Tools for Regulated Teams — the compliance and masking-vs-synthetic angle