OpenAI API vs Convex
Frontier models: GPT-5, o-series reasoning, image, audio, embeddings
vs. The reactive database where queries are TypeScript code
Pricing tiers
OpenAI API
Free Tier (Trial)
$5 free credit for new accounts. Rate-limited.
Free
Pay-as-you-go
No monthly min. Per-token pricing by model.
$0 base (usage-based)
Usage Tiers (1-5)
Automatic tier promotion based on cumulative spend. Higher tiers = higher rate limits + new model access.
$0 base (usage-based)
Enterprise
Custom. Priority access, SLA, dedicated capacity.
Custom
Convex
Starter (Free)
Free with overage via usage-based billing. Great for prototypes.
Free
Professional
$25/developer/month. Overage: $2/M function calls. Daily backups, email support, custom domains.
$25/mo
Business / Enterprise
From $2,500/month. SAML/SSO, SLA, dedicated deployments, Slack Connect support.
$2500/mo
Free-tier quotas head-to-head
Comparing free-tier on OpenAI API vs starter on Convex.
| Metric | OpenAI API | Convex |
|---|---|---|
| db storage gb | — | 0.5 GB |
| deployments | — | 40 deployments |
| egress gb month | — | 1 GB/month |
| file storage gb | — | 1 GB |
| function calls month | — | 1000000 calls/month |
| team members | — | 6 users |
Features
OpenAI API · 12 features
- Assistants API — Stateful assistants with tools, threads, file search.
- Batch API — 50% discount for async processing within 24h.
- Chat Completions API — Classic /v1/chat/completions endpoint.
- Files API — Upload docs for retrieval, fine-tuning, batch.
- Fine-Tuning — Supervised + DPO fine-tuning for GPT-4o, GPT-4.1, GPT-4o-mini.
- Function Calling — JSON-schema tool calling; parallel calls supported.
- Moderation — Safety classifier API (free).
- Prompt Caching — Auto-cache repeated prefixes; 50% cheaper cached hits.
- Realtime API — WebSocket streaming voice + text with low latency.
- Responses API — Stateful conversational API.
- Structured Outputs — Enforced JSON schema compliance.
- Vision — Image input for GPT models.
Convex · 18 features
- Actions — Non-deterministic functions for external I/O (fetch, AI APIs, email). Cannot rea…
- Authentication — Convex Auth (built-in) or BYO provider (Clerk, Auth0, Kinde, WorkOS). ID tokens …
- Convex Agents — AI agent framework with durable memory, threads, tool use. Works with OpenAI / A…
- Convex Auth — First-party auth library: passwords, magic links, OAuth, phone — stored in your …
- Convex Components — Reusable backend modules (rate limiter, workflow, aggregate, action-retrier, etc…
- Cron Jobs — Recurring schedules defined in convex/crons.ts. UTC, cron-style patterns.
- Durable Workflows — Long-running multi-step workflows with retries and at-least-once guarantees.
- Exception Reporting — Auto-capture errors to Sentry, Axiom, Datadog.
- File Storage — Upload/download via storage API. Returns storage IDs referenced in documents.
- Full-Text Search — BM25 search index on table fields. withSearchIndex query helper.
- HTTP Actions — Expose public HTTP endpoints for webhooks, OAuth callbacks, third-party integrat…
- Log Streams — Stream function logs to Axiom, Datadog, Sentry. Pro+.
- Mutations — Transactional write functions. All reads + writes in one mutation are ACID; conf…
- Preview Deployments — Every Git branch gets its own isolated deployment. Integrates with Vercel/Netlif…
- Queries — Deterministic read-only TS functions. Automatically cached and re-run when under…
- Real-Time Subscriptions — useQuery auto-subscribes; server invalidates when data a query read changes. No …
- Scheduler — schedule.after / schedule.at — enqueue functions to run later. Durable, survives…
- Vector Search — Native vector index on tables. withIndex + filter fields. Up to 4096 dims.
Developer interfaces
| Kind | OpenAI API | Convex |
|---|---|---|
| CLI | — | Convex CLI |
| SDK | openai-dotnet, openai-go, openai-node, openai-python | Android / Kotlin Client, iOS / Swift Client, JavaScript/TypeScript Client, Next.js Integration, Python Client, React Client (useQuery), Rust Client, Svelte Client, Vue Client |
| REST | OpenAI REST API | Deploy / Dashboard API, HTTP Actions |
| MCP | OpenAI MCP | — |
| OTHER | Realtime API (WebSocket) | WebSocket Subscriptions |
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