Best Free Movie Streaming Sites Compared (2026) — Vidsrc vs Alternatives
Every movie and TV show on the web has at least two identities: the one assigned by IMDb and the one assigned by TMDB. They point at the same titles, they look different on the page, and they behave differently when you feed them into an embed player. This guide explains what each identifier is, how the formats differ, why Vidsrc accepts both, and how to pick the right one for the kind of site you run.
By the end of this article you will know exactly when to reach for an IMDb identifier, when a TMDB identifier saves you time, and how to map between the two when your catalog only has one of them.
What an IMDb ID actually is
The IMDb identifier is the alphanumeric string that appears in the URL of every title page on IMDb. It always begins with tt, is followed by seven or eight digits, and is unique to a single title. A movie gets one identifier, a TV series gets one identifier at the root level, and each episode of that series gets its own identifier as well.
The format has been stable for decades, which is why so many tools and datasets default to it. If you scrape a movie page, copy a link from a review site, or import a list from a third-party catalog, the identifier you end up with is almost always the IMDb one. It is also the identifier most human readers recognise, because they have seen it on IMDb for years.
What a TMDB ID actually is
The TMDB identifier is a plain integer assigned by The Movie Database. It appears in the URL of the title page on TMDB and in every response from the TMDB API. There is no tt prefix, no leading zeros, no checksum — just a number. Like IMDb, TMDB assigns a root identifier to a series and additional identifiers to each season and episode.
TMDB's API is the primary reason developers reach for TMDB identifiers first. The metadata schema is richer, the API is well documented, and the identifier maps cleanly to TMDB's own poster, backdrop, and cast data. If you are building a catalog-driven site, you probably already have TMDB identifiers in your database.
Format differences at a glance
IMDb looks like tt0111161. TMDB looks like 550. Both refer to the same prison drama. The shorter TMDB form is easier to pass through query strings and shorter to display in URLs, but the IMDb form is what most readers recognise from years of seeing it in trailers and on the IMDb app.
Why Vidsrc supports both
Vidsrc accepts both identifiers on every public build endpoint because no single identifier fits every workflow. Some integrations start from an IMDb URL the user pastes in; others start from a TMDB API response the developer fetched at build time. Forcing every caller to convert to one format would add a step for everyone, so the endpoints accept either and resolve them to the same internal title.
Internally, Vidsrc treats the two identifiers as interchangeable handles for the same underlying record. You can mix them within a single site, switch from one to the other with a single query parameter change, and never worry about cross-system drift. The response from a build endpoint is identical in shape regardless of which identifier you passed in.
When to use which
Use an IMDb identifier when
You are copying identifiers out of an existing dataset that uses them, your readers are likely to recognise them, or your workflow begins with a user pasting an IMDb URL into a form on your site. IMDb identifiers are also the safer choice for titles that have been recently renamed or merged, because IMDb's editorial process catches those changes quickly.
Use a TMDB identifier when
You are pulling metadata from the TMDB API and want to avoid a second round trip to resolve identifiers, you need the shorter numeric form for display reasons, or your entire catalog is already keyed by TMDB. TMDB identifiers are also slightly more stable for very new titles, because TMDB often indexes a new release before other databases update.
Pros and cons of each
IMDb identifiers are ubiquitous and human-readable, but they change occasionally when titles are merged or split, and the alphanumeric form is harder to type from memory. TMDB identifiers are short and stable for new content, but they are not as widely recognised by casual readers, and the TMDB API requires a key for full access.
How to find each identifier
On IMDb
Open the title's page on IMDb and look at the URL. The string that starts with tt is the identifier. For TV shows, make sure you are on the root series page, not an episode page, before you copy the identifier.
On TMDB
Open the title's page on TMDB and look at the URL. The trailing number is the identifier. The TMDB API also returns the identifier in every response, so a programmatic workflow can capture it alongside the metadata in a single call.
API mapping between the two
The TMDB API exposes an external_ids endpoint for any movie, TV show, or episode that returns the matching IMDb identifier, which makes one-to-one mapping straightforward. If you only have an IMDb identifier, the public Vidsrc build endpoint will return the TMDB identifier as part of its response, so you can populate the missing field on the fly.