DecentDB vs Firebird Embedded: When to Choose Which¶

This document helps developers decide between DecentDB and Firebird Embedded for local SQL workloads. Both can be embedded into applications, but they come from different database traditions.

Versions compared: DecentDB 2.15.0 workspace behavior vs public Firebird Embedded and Firebird feature documentation as of 2026-06-28.

Scope note: Firebird is a full SQL relational database system with server and embedded deployment options. This page focuses on the embedded deployment option, where the engine is linked into the application process through the Firebird client/API libraries.

See also: DecentDB vs SQLite, DecentDB vs H2, SQL Feature Matrix, and SQL Reference.

They Are Both SQL Engines, But Not the Same Kind of Embedded Product¶

Firebird Embedded is a full-featured Firebird engine packaged for local embedding. Firebird documents the embedded server as having the same features as the usual server, with local protocol constraints in embedded mode.

DecentDB is a newer Rust-native embedded database designed around local application data, durable-by-default writes, multi-language bindings, local branch/sync workflows, policies/masks, and a focused SQL surface.

The short version:

• Choose Firebird Embedded when you want the Firebird SQL engine, Firebird's stored procedure/trigger ecosystem, and a path between embedded and server-style Firebird deployments.
• Choose DecentDB when you want a small Rust-native embedded database with DecentDB-native branch, sync, policy, diagnostics, and binding workflows.

At a Glance¶

When DecentDB Is the Better Fit¶

1. You want a lightweight embedded application database, not a server-derived engine¶

Firebird Embedded is powerful because it is Firebird. That can also make it more database-server-like in packaging, dependencies, SQL dialect, tooling, and operational expectations.

DecentDB is designed first as an embedded application database:

use decentdb::{Db, DbConfig};

let db = Db::open("app.ddb", DbConfig::default())?;

If the database should feel like a small local component shipped with an application, DecentDB may be easier to reason about.

2. You need DecentDB's local branch, diff, and restore workflows¶

DecentDB makes local database change validation explicit:

decentdb snapshot create --db app.ddb --name before-upgrade
decentdb branch create --db app.ddb --name upgrade-test --from before-upgrade
decentdb branch diff --db app.ddb --left main --right upgrade-test --format table
decentdb branch merge --db app.ddb --source upgrade-test --target main --dry-run

Firebird has mature backup/restore and transaction capabilities, but branch and diff are not the same product-level local workflow. Choose DecentDB when those workflows are central to the application.

3. You need local-first sync state in SQL/CLI¶

DecentDB exposes sync state, peers, scopes, conflicts, retention, and doctor checks as local database surfaces:

SELECT * FROM sys_sync_status;
SELECT * FROM sys_sync_journal ORDER BY sequence DESC LIMIT 20;
SELECT * FROM sys_sync_conflicts;
SELECT * FROM sys_sync_doctor;

Firebird can be used in replicated systems, but Firebird Embedded is not primarily a local-first sync product. If offline exchange, conflict inspection, and sync diagnostics should be built into the embedded database, DecentDB is the closer fit.

4. You need embedded row policies, projection masks, and audit context¶

DecentDB includes local policy/masking features:

SET AUDIT CONTEXT tenant_id = 'tenant-a';

CREATE POLICY tenant_filter ON invoices
USING tenant_id = current_tenant();

CREATE MASK salary_mask ON employees(salary)
USING NULL;

Firebird has a serious SQL engine and security model, including stored procedures and triggers. DecentDB's value is narrower and local-app-specific: policy and mask rules are engine-enforced features of the embedded database.

5. You want Postgres-style application SQL in a focused embedded engine¶

DecentDB supports useful Postgres-style syntax:

SELECT DISTINCT ON (account_id)
       account_id, event_id, created_at
FROM account_events
ORDER BY account_id, created_at DESC;

INSERT INTO users (email) VALUES ($1) RETURNING id;

Firebird SQL is its own mature dialect. If your application already speaks Firebird SQL, Firebird Embedded is a natural choice. If you prefer DecentDB's Postgres-adjacent subset, DecentDB is a cleaner fit.

6. You need multi-language bindings around one small C ABI¶

DecentDB's public embedding strategy is a stable C ABI with maintained bindings:

• Rust;
• C/C++;
• Python;
• .NET;
• Go;
• Java;
• Node.js;
• Dart.

Firebird has mature drivers and APIs across ecosystems. DecentDB's distinction is that these bindings are part of one small embedded database project's contract and release process.

7. You need deterministic crash/fault validation hooks¶

DecentDB includes FaultyVFS and WAL failpoint validation in its durability testing strategy. Choose DecentDB when local crash behavior is something you want to test directly through the engine's fault-injection tooling.

Firebird is mature and battle-tested, but the two projects expose different testing surfaces to application developers.

When Firebird Embedded Is the Better Fit¶

1. You already use Firebird SQL or Firebird tooling¶

If your schema, queries, stored procedures, triggers, backup workflow, and team knowledge are already Firebird-shaped, Firebird Embedded is the natural local engine.

Moving to DecentDB would be a real database migration: SQL dialect changes, driver changes, feature review, and data migration.

2. You need mature stored procedures and PSQL¶

Firebird's procedural SQL is a major differentiator:

-- Firebird-style stored procedure direction.
CREATE PROCEDURE recompute_account_balance (account_id INTEGER)
AS
BEGIN
  -- procedural SQL body
END

DecentDB supports triggers and sandboxed Lua extension packages, but it does not provide Firebird's mature PSQL stored procedure environment. If database resident procedural logic is central, Firebird Embedded is stronger.

3. You want a path from embedded to server-style Firebird deployments¶

Firebird Embedded belongs to the same engine family as Firebird server deployments. That can matter when an application might start local and later move to a server topology, or when teams already operate Firebird elsewhere.

DecentDB is intentionally embedded. It does not currently offer a DecentDB server deployment path.

4. You need Firebird's SQL dialect and ecosystem features¶

Firebird supports a broad SQL feature set, stored procedures, triggers, common table expressions, flexible transaction management, monitoring tables, Trace API, events, and Firebird-specific tooling.

If those are application requirements, Firebird Embedded is a better fit than asking DecentDB to become Firebird-compatible.

5. You rely on Firebird's multi-generational architecture¶

Firebird is known for its multi-generational architecture and concurrency model. If your application already benefits from Firebird's transaction semantics or concurrency behavior, preserve that advantage unless DecentDB's native features justify a migration.

6. You need existing Firebird drivers and support knowledge¶

Firebird has established drivers and knowledge in Delphi, C/C++, Java, .NET, ODBC, and other ecosystems. DecentDB has maintained bindings, but it does not replace Firebird's ecosystem history.

Side-by-Side Examples¶

Firebird-centered application¶

-- Firebird direction: database-side procedural SQL and Firebird tooling.
CREATE TRIGGER orders_ai FOR orders
ACTIVE AFTER INSERT POSITION 0
AS
BEGIN
  -- Firebird PSQL trigger body
END

Prefer Firebird Embedded when the application is built around Firebird SQL, PSQL, and Firebird deployment knowledge.

DecentDB local-first application¶

-- DecentDB direction: local sync inspection and policy/mask behavior.
SELECT * FROM sys_sync_status;

CREATE POLICY tenant_scope ON invoices
USING tenant_id = current_tenant();

Prefer DecentDB when local sync state, branch workflows, and local data governance are the differentiators.

Server migration path¶

Firebird Embedded -> Firebird server-family deployment

Prefer Firebird Embedded if the architecture may need to become a Firebird server deployment later.

DecentDB local file -> DecentDB local sync / branch / restore workflows

Prefer DecentDB if the architecture is intentionally local-first embedded rather than server-transition-oriented.

Summary Decision Matrix¶

Bottom Line¶

Pick Firebird Embedded when you want Firebird locally: Firebird SQL, stored procedures, triggers, mature drivers, and a path toward Firebird server deployments.

Pick DecentDB when you want a Rust-native embedded database with durable defaults, branchable local data, inspectable sync, policy/mask features, and a focused multi-language embedding story.

Both are credible embedded SQL choices. The right decision depends on whether your application wants the Firebird ecosystem or DecentDB's local application database workflows.

External References¶

• Firebird Embedded server notes
• Firebird Windows Embedded documentation
• Firebird features
• Firebird project home
• Firebird documentation index